drivers/md/raid10.c

   1 /*
   2  * raid10.c : Multiple Devices driver for Linux
   3  *
   4  * Copyright (C) 2000-2004 Neil Brown
   5  *
   6  * RAID-10 support for md.
   7  *
   8  * Base on code in raid1.c.  See raid1.c for further copyright information.
   9  *
  10  *
  11  * This program is free software; you can redistribute it and/or modify
  12  * it under the terms of the GNU General Public License as published by
  13  * the Free Software Foundation; either version 2, or (at your option)
  14  * any later version.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * (for example /usr/src/linux/COPYING); if not, write to the Free
  18  * Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  19  */
  20
  21 #include <linux/slab.h>
  22 #include <linux/delay.h>
  23 #include <linux/blkdev.h>
  24 #include <linux/module.h>
  25 #include <linux/seq_file.h>
  26 #include <linux/ratelimit.h>
  27 #include <linux/kthread.h>
  28 #include "md.h"
  29 #include "raid10.h"
  30 #include "raid0.h"
  31 #include "bitmap.h"
  32
  33 /*
  34  * RAID10 provides a combination of RAID0 and RAID1 functionality.
  35  * The layout of data is defined by
  36  *    chunk_size
  37  *    raid_disks
  38  *    near_copies (stored in low byte of layout)
  39  *    far_copies (stored in second byte of layout)
  40  *    far_offset (stored in bit 16 of layout )
  41  *    use_far_sets (stored in bit 17 of layout )
  42  *    use_far_sets_bugfixed (stored in bit 18 of layout )
  43  *
  44  * The data to be stored is divided into chunks using chunksize.  Each device
  45  * is divided into far_copies sections.   In each section, chunks are laid out
  46  * in a style similar to raid0, but near_copies copies of each chunk is stored
  47  * (each on a different drive).  The starting device for each section is offset
  48  * near_copies from the starting device of the previous section.  Thus there
  49  * are (near_copies * far_copies) of each chunk, and each is on a different
  50  * drive.  near_copies and far_copies must be at least one, and their product
  51  * is at most raid_disks.
  52  *
  53  * If far_offset is true, then the far_copies are handled a bit differently.
  54  * The copies are still in different stripes, but instead of being very far
  55  * apart on disk, there are adjacent stripes.
  56  *
  57  * The far and offset algorithms are handled slightly differently if
  58  * 'use_far_sets' is true.  In this case, the array's devices are grouped into
  59  * sets that are (near_copies * far_copies) in size.  The far copied stripes
  60  * are still shifted by 'near_copies' devices, but this shifting stays confined
  61  * to the set rather than the entire array.  This is done to improve the number
  62  * of device combinations that can fail without causing the array to fail.
  63  * Example 'far' algorithm w/o 'use_far_sets' (each letter represents a chunk
  64  * on a device):
  65  *    A B C D    A B C D E
  66  *      ...         ...
  67  *    D A B C    E A B C D
  68  * Example 'far' algorithm w/ 'use_far_sets' enabled (sets illustrated w/ []'s):
  69  *    [A B] [C D]    [A B] [C D E]
  70  *    |...| |...|    |...| | ... |
  71  *    [B A] [D C]    [B A] [E C D]
  72  */
  73
  74 /*
  75  * Number of guaranteed r10bios in case of extreme VM load:
  76  */
  77 #define NR_RAID10_BIOS 256
  78
  79 /* when we get a read error on a read-only array, we redirect to another
  80  * device without failing the first device, or trying to over-write to
  81  * correct the read error.  To keep track of bad blocks on a per-bio
  82  * level, we store IO_BLOCKED in the appropriate 'bios' pointer
  83  */
  84 #define IO_BLOCKED ((struct bio *)1)
  85 /* When we successfully write to a known bad-block, we need to remove the
  86  * bad-block marking which must be done from process context.  So we record
  87  * the success by setting devs[n].bio to IO_MADE_GOOD
  88  */
  89 #define IO_MADE_GOOD ((struct bio *)2)
  90
  91 #define BIO_SPECIAL(bio) ((unsigned long)bio <= 2)
  92
  93 /* When there are this many requests queued to be written by
  94  * the raid10 thread, we become 'congested' to provide back-pressure
  95  * for writeback.
  96  */
  97 static int max_queued_requests = 1024;
  98
  99 static void allow_barrier(struct r10conf *conf);
 100 static void lower_barrier(struct r10conf *conf);
 101 static int _enough(struct r10conf *conf, int previous, int ignore);
 102 static sector_t reshape_request(struct mddev *mddev, sector_t sector_nr,
 103                                 int *skipped);
 104 static void reshape_request_write(struct mddev *mddev, struct r10bio *r10_bio);
 105 static void end_reshape_write(struct bio *bio);
 106 static void end_reshape(struct r10conf *conf);
 107
 108 static void * r10bio_pool_alloc(gfp_t gfp_flags, void *data)
 109 {
 110         struct r10conf *conf = data;
 111         int size = offsetof(struct r10bio, devs[conf->copies]);
 112
 113         /* allocate a r10bio with room for raid_disks entries in the
 114          * bios array */
 115         return kzalloc(size, gfp_flags);
 116 }
 117
 118 static void r10bio_pool_free(void *r10_bio, void *data)
 119 {
 120         kfree(r10_bio);
 121 }
 122
 123 /* Maximum size of each resync request */
 124 #define RESYNC_BLOCK_SIZE (64*1024)
 125 #define RESYNC_PAGES ((RESYNC_BLOCK_SIZE + PAGE_SIZE-1) / PAGE_SIZE)
 126 /* amount of memory to reserve for resync requests */
 127 #define RESYNC_WINDOW (1024*1024)
 128 /* maximum number of concurrent requests, memory permitting */
 129 #define RESYNC_DEPTH (32*1024*1024/RESYNC_BLOCK_SIZE)
 130
 131 /*
 132  * When performing a resync, we need to read and compare, so
 133  * we need as many pages are there are copies.
 134  * When performing a recovery, we need 2 bios, one for read,
 135  * one for write (we recover only one drive per r10buf)
 136  *
 137  */
 138 static void * r10buf_pool_alloc(gfp_t gfp_flags, void *data)
 139 {
 140         struct r10conf *conf = data;
 141         struct page *page;
 142         struct r10bio *r10_bio;
 143         struct bio *bio;
 144         int i, j;
 145         int nalloc;
 146
 147         r10_bio = r10bio_pool_alloc(gfp_flags, conf);
 148         if (!r10_bio)
 149                 return NULL;
 150
 151         if (test_bit(MD_RECOVERY_SYNC, &conf->mddev->recovery) ||
 152             test_bit(MD_RECOVERY_RESHAPE, &conf->mddev->recovery))
 153                 nalloc = conf->copies; /* resync */
 154         else
 155                 nalloc = 2; /* recovery */
 156
 157         /*
 158          * Allocate bios.
 159          */
 160         for (j = nalloc ; j-- ; ) {
 161                 bio = bio_kmalloc(gfp_flags, RESYNC_PAGES);
 162                 if (!bio)
 163                         goto out_free_bio;
 164                 r10_bio->devs[j].bio = bio;
 165                 if (!conf->have_replacement)
 166                         continue;
 167                 bio = bio_kmalloc(gfp_flags, RESYNC_PAGES);
 168                 if (!bio)
 169                         goto out_free_bio;
 170                 r10_bio->devs[j].repl_bio = bio;
 171         }
 172         /*
 173          * Allocate RESYNC_PAGES data pages and attach them
 174          * where needed.
 175          */
 176         for (j = 0 ; j < nalloc; j++) {
 177                 struct bio *rbio = r10_bio->devs[j].repl_bio;
 178                 bio = r10_bio->devs[j].bio;
 179                 for (i = 0; i < RESYNC_PAGES; i++) {
 180                         if (j > 0 && !test_bit(MD_RECOVERY_SYNC,
 181                                                &conf->mddev->recovery)) {
 182                                 /* we can share bv_page's during recovery
 183                                  * and reshape */
 184                                 struct bio *rbio = r10_bio->devs[0].bio;
 185                                 page = rbio->bi_io_vec[i].bv_page;
 186                                 get_page(page);
 187                         } else
 188                                 page = alloc_page(gfp_flags);
 189                         if (unlikely(!page))
 190                                 goto out_free_pages;
 191
 192                         bio->bi_io_vec[i].bv_page = page;
 193                         if (rbio)
 194                                 rbio->bi_io_vec[i].bv_page = page;
 195                 }
 196         }
 197
 198         return r10_bio;
 199
 200 out_free_pages:
 201         for ( ; i > 0 ; i--)
 202                 safe_put_page(bio->bi_io_vec[i-1].bv_page);
 203         while (j--)
 204                 for (i = 0; i < RESYNC_PAGES ; i++)
 205                         safe_put_page(r10_bio->devs[j].bio->bi_io_vec[i].bv_page);
 206         j = 0;
 207 out_free_bio:
 208         for ( ; j < nalloc; j++) {
 209                 if (r10_bio->devs[j].bio)
 210                         bio_put(r10_bio->devs[j].bio);
 211                 if (r10_bio->devs[j].repl_bio)
 212                         bio_put(r10_bio->devs[j].repl_bio);
 213         }
 214         r10bio_pool_free(r10_bio, conf);
 215         return NULL;
 216 }
 217
 218 static void r10buf_pool_free(void *__r10_bio, void *data)
 219 {
 220         int i;
 221         struct r10conf *conf = data;
 222         struct r10bio *r10bio = __r10_bio;
 223         int j;
 224
 225         for (j=0; j < conf->copies; j++) {
 226                 struct bio *bio = r10bio->devs[j].bio;
 227                 if (bio) {
 228                         for (i = 0; i < RESYNC_PAGES; i++) {
 229                                 safe_put_page(bio->bi_io_vec[i].bv_page);
 230                                 bio->bi_io_vec[i].bv_page = NULL;
 231                         }
 232                         bio_put(bio);
 233                 }
 234                 bio = r10bio->devs[j].repl_bio;
 235                 if (bio)
 236                         bio_put(bio);
 237         }
 238         r10bio_pool_free(r10bio, conf);
 239 }
 240
 241 static void put_all_bios(struct r10conf *conf, struct r10bio *r10_bio)
 242 {
 243         int i;
 244
 245         for (i = 0; i < conf->copies; i++) {
 246                 struct bio **bio = & r10_bio->devs[i].bio;
 247                 if (!BIO_SPECIAL(*bio))
 248                         bio_put(*bio);
 249                 *bio = NULL;
 250                 bio = &r10_bio->devs[i].repl_bio;
 251                 if (r10_bio->read_slot < 0 && !BIO_SPECIAL(*bio))
 252                         bio_put(*bio);
 253                 *bio = NULL;
 254         }
 255 }
 256
 257 static void free_r10bio(struct r10bio *r10_bio)
 258 {
 259         struct r10conf *conf = r10_bio->mddev->private;
 260
 261         put_all_bios(conf, r10_bio);
 262         mempool_free(r10_bio, conf->r10bio_pool);
 263 }
 264
 265 static void put_buf(struct r10bio *r10_bio)
 266 {
 267         struct r10conf *conf = r10_bio->mddev->private;
 268
 269         mempool_free(r10_bio, conf->r10buf_pool);
 270
 271         lower_barrier(conf);
 272 }
 273
 274 static void reschedule_retry(struct r10bio *r10_bio)
 275 {
 276         unsigned long flags;
 277         struct mddev *mddev = r10_bio->mddev;
 278         struct r10conf *conf = mddev->private;
 279
 280         spin_lock_irqsave(&conf->device_lock, flags);
 281         list_add(&r10_bio->retry_list, &conf->retry_list);
 282         conf->nr_queued ++;
 283         spin_unlock_irqrestore(&conf->device_lock, flags);
 284
 285         /* wake up frozen array... */
 286         wake_up(&conf->wait_barrier);
 287
 288         md_wakeup_thread(mddev->thread);
 289 }
 290
 291 /*
 292  * raid_end_bio_io() is called when we have finished servicing a mirrored
 293  * operation and are ready to return a success/failure code to the buffer
 294  * cache layer.
 295  */
 296 static void raid_end_bio_io(struct r10bio *r10_bio)
 297 {
 298         struct bio *bio = r10_bio->master_bio;
 299         int done;
 300         struct r10conf *conf = r10_bio->mddev->private;
 301
 302         if (bio->bi_phys_segments) {
 303                 unsigned long flags;
 304                 spin_lock_irqsave(&conf->device_lock, flags);
 305                 bio->bi_phys_segments--;
 306                 done = (bio->bi_phys_segments == 0);
 307                 spin_unlock_irqrestore(&conf->device_lock, flags);
 308         } else
 309                 done = 1;
 310         if (!test_bit(R10BIO_Uptodate, &r10_bio->state))
 311                 bio->bi_error = -EIO;
 312         if (done) {
 313                 bio_endio(bio);
 314                 /*
 315                  * Wake up any possible resync thread that waits for the device
 316                  * to go idle.
 317                  */
 318                 allow_barrier(conf);
 319         }
 320         free_r10bio(r10_bio);
 321 }
 322
 323 /*
 324  * Update disk head position estimator based on IRQ completion info.
 325  */
 326 static inline void update_head_pos(int slot, struct r10bio *r10_bio)
 327 {
 328         struct r10conf *conf = r10_bio->mddev->private;
 329
 330         conf->mirrors[r10_bio->devs[slot].devnum].head_position =
 331                 r10_bio->devs[slot].addr + (r10_bio->sectors);
 332 }
 333
 334 /*
 335  * Find the disk number which triggered given bio
 336  */
 337 static int find_bio_disk(struct r10conf *conf, struct r10bio *r10_bio,
 338                          struct bio *bio, int *slotp, int *replp)
 339 {
 340         int slot;
 341         int repl = 0;
 342
 343         for (slot = 0; slot < conf->copies; slot++) {
 344                 if (r10_bio->devs[slot].bio == bio)
 345                         break;
 346                 if (r10_bio->devs[slot].repl_bio == bio) {
 347                         repl = 1;
 348                         break;
 349                 }
 350         }
 351
 352         BUG_ON(slot == conf->copies);
 353         update_head_pos(slot, r10_bio);
 354
 355         if (slotp)
 356                 *slotp = slot;
 357         if (replp)
 358                 *replp = repl;
 359         return r10_bio->devs[slot].devnum;
 360 }
 361
 362 static void raid10_end_read_request(struct bio *bio)
 363 {
 364         int uptodate = !bio->bi_error;
 365         struct r10bio *r10_bio = bio->bi_private;
 366         int slot, dev;
 367         struct md_rdev *rdev;
 368         struct r10conf *conf = r10_bio->mddev->private;
 369
 370         slot = r10_bio->read_slot;
 371         dev = r10_bio->devs[slot].devnum;
 372         rdev = r10_bio->devs[slot].rdev;
 373         /*
 374          * this branch is our 'one mirror IO has finished' event handler:
 375          */
 376         update_head_pos(slot, r10_bio);
 377
 378         if (uptodate) {
 379                 /*
 380                  * Set R10BIO_Uptodate in our master bio, so that
 381                  * we will return a good error code to the higher
 382                  * levels even if IO on some other mirrored buffer fails.
 383                  *
 384                  * The 'master' represents the composite IO operation to
 385                  * user-side. So if something waits for IO, then it will
 386                  * wait for the 'master' bio.
 387                  */
 388                 set_bit(R10BIO_Uptodate, &r10_bio->state);
 389         } else {
 390                 /* If all other devices that store this block have
 391                  * failed, we want to return the error upwards rather
 392                  * than fail the last device.  Here we redefine
 393                  * "uptodate" to mean "Don't want to retry"
 394                  */
 395                 if (!_enough(conf, test_bit(R10BIO_Previous, &r10_bio->state),
 396                              rdev->raid_disk))
 397                         uptodate = 1;
 398         }
 399         if (uptodate) {
 400                 raid_end_bio_io(r10_bio);
 401                 rdev_dec_pending(rdev, conf->mddev);
 402         } else {
 403                 /*
 404                  * oops, read error - keep the refcount on the rdev
 405                  */
 406                 char b[BDEVNAME_SIZE];
 407                 printk_ratelimited(KERN_ERR
 408                                    "md/raid10:%s: %s: rescheduling sector %llu\n",
 409                                    mdname(conf->mddev),
 410                                    bdevname(rdev->bdev, b),
 411                                    (unsigned long long)r10_bio->sector);
 412                 set_bit(R10BIO_ReadError, &r10_bio->state);
 413                 reschedule_retry(r10_bio);
 414         }
 415 }
 416
 417 static void close_write(struct r10bio *r10_bio)
 418 {
 419         /* clear the bitmap if all writes complete successfully */
 420         bitmap_endwrite(r10_bio->mddev->bitmap, r10_bio->sector,
 421                         r10_bio->sectors,
 422                         !test_bit(R10BIO_Degraded, &r10_bio->state),
 423                         0);
 424         md_write_end(r10_bio->mddev);
 425 }
 426
 427 static void one_write_done(struct r10bio *r10_bio)
 428 {
 429         if (atomic_dec_and_test(&r10_bio->remaining)) {
 430                 if (test_bit(R10BIO_WriteError, &r10_bio->state))
 431                         reschedule_retry(r10_bio);
 432                 else {
 433                         close_write(r10_bio);
 434                         if (test_bit(R10BIO_MadeGood, &r10_bio->state))
 435                                 reschedule_retry(r10_bio);
 436                         else
 437                                 raid_end_bio_io(r10_bio);
 438                 }
 439         }
 440 }
 441
 442 static void raid10_end_write_request(struct bio *bio)
 443 {
 444         struct r10bio *r10_bio = bio->bi_private;
 445         int dev;
 446         int dec_rdev = 1;
 447         struct r10conf *conf = r10_bio->mddev->private;
 448         int slot, repl;
 449         struct md_rdev *rdev = NULL;
 450
 451         dev = find_bio_disk(conf, r10_bio, bio, &slot, &repl);
 452
 453         if (repl)
 454                 rdev = conf->mirrors[dev].replacement;
 455         if (!rdev) {
 456                 smp_rmb();
 457                 repl = 0;
 458                 rdev = conf->mirrors[dev].rdev;
 459         }
 460         /*
 461          * this branch is our 'one mirror IO has finished' event handler:
 462          */
 463         if (bio->bi_error) {
 464                 if (repl)
 465                         /* Never record new bad blocks to replacement,
 466                          * just fail it.
 467                          */
 468                         md_error(rdev->mddev, rdev);
 469                 else {
 470                         set_bit(WriteErrorSeen, &rdev->flags);
 471                         if (!test_and_set_bit(WantReplacement, &rdev->flags))
 472                                 set_bit(MD_RECOVERY_NEEDED,
 473                                         &rdev->mddev->recovery);
 474                         set_bit(R10BIO_WriteError, &r10_bio->state);
 475                         dec_rdev = 0;
 476                 }
 477         } else {
 478                 /*
 479                  * Set R10BIO_Uptodate in our master bio, so that
 480                  * we will return a good error code for to the higher
 481                  * levels even if IO on some other mirrored buffer fails.
 482                  *
 483                  * The 'master' represents the composite IO operation to
 484                  * user-side. So if something waits for IO, then it will
 485                  * wait for the 'master' bio.
 486                  */
 487                 sector_t first_bad;
 488                 int bad_sectors;
 489
 490                 /*
 491                  * Do not set R10BIO_Uptodate if the current device is
 492                  * rebuilding or Faulty. This is because we cannot use
 493                  * such device for properly reading the data back (we could
 494                  * potentially use it, if the current write would have felt
 495                  * before rdev->recovery_offset, but for simplicity we don't
 496                  * check this here.
 497                  */
 498                 if (test_bit(In_sync, &rdev->flags) &&
 499                     !test_bit(Faulty, &rdev->flags))
 500                         set_bit(R10BIO_Uptodate, &r10_bio->state);
 501
 502                 /* Maybe we can clear some bad blocks. */
 503                 if (is_badblock(rdev,
 504                                 r10_bio->devs[slot].addr,
 505                                 r10_bio->sectors,
 506                                 &first_bad, &bad_sectors)) {
 507                         bio_put(bio);
 508                         if (repl)
 509                                 r10_bio->devs[slot].repl_bio = IO_MADE_GOOD;
 510                         else
 511                                 r10_bio->devs[slot].bio = IO_MADE_GOOD;
 512                         dec_rdev = 0;
 513                         set_bit(R10BIO_MadeGood, &r10_bio->state);
 514                 }
 515         }
 516
 517         /*
 518          *
 519          * Let's see if all mirrored write operations have finished
 520          * already.
 521          */
 522         one_write_done(r10_bio);
 523         if (dec_rdev)
 524                 rdev_dec_pending(rdev, conf->mddev);
 525 }
 526
 527 /*
 528  * RAID10 layout manager
 529  * As well as the chunksize and raid_disks count, there are two
 530  * parameters: near_copies and far_copies.
 531  * near_copies * far_copies must be <= raid_disks.
 532  * Normally one of these will be 1.
 533  * If both are 1, we get raid0.
 534  * If near_copies == raid_disks, we get raid1.
 535  *
 536  * Chunks are laid out in raid0 style with near_copies copies of the
 537  * first chunk, followed by near_copies copies of the next chunk and
 538  * so on.
 539  * If far_copies > 1, then after 1/far_copies of the array has been assigned
 540  * as described above, we start again with a device offset of near_copies.
 541  * So we effectively have another copy of the whole array further down all
 542  * the drives, but with blocks on different drives.
 543  * With this layout, and block is never stored twice on the one device.
 544  *
 545  * raid10_find_phys finds the sector offset of a given virtual sector
 546  * on each device that it is on.
 547  *
 548  * raid10_find_virt does the reverse mapping, from a device and a
 549  * sector offset to a virtual address
 550  */
 551
 552 static void __raid10_find_phys(struct geom *geo, struct r10bio *r10bio)
 553 {
 554         int n,f;
 555         sector_t sector;
 556         sector_t chunk;
 557         sector_t stripe;
 558         int dev;
 559         int slot = 0;
 560         int last_far_set_start, last_far_set_size;
 561
 562         last_far_set_start = (geo->raid_disks / geo->far_set_size) - 1;
 563         last_far_set_start *= geo->far_set_size;
 564
 565         last_far_set_size = geo->far_set_size;
 566         last_far_set_size += (geo->raid_disks % geo->far_set_size);
 567
 568         /* now calculate first sector/dev */
 569         chunk = r10bio->sector >> geo->chunk_shift;
 570         sector = r10bio->sector & geo->chunk_mask;
 571
 572         chunk *= geo->near_copies;
 573         stripe = chunk;
 574         dev = sector_div(stripe, geo->raid_disks);
 575         if (geo->far_offset)
 576                 stripe *= geo->far_copies;
 577
 578         sector += stripe << geo->chunk_shift;
 579
 580         /* and calculate all the others */
 581         for (n = 0; n < geo->near_copies; n++) {
 582                 int d = dev;
 583                 int set;
 584                 sector_t s = sector;
 585                 r10bio->devs[slot].devnum = d;
 586                 r10bio->devs[slot].addr = s;
 587                 slot++;
 588
 589                 for (f = 1; f < geo->far_copies; f++) {
 590                         set = d / geo->far_set_size;
 591                         d += geo->near_copies;
 592
 593                         if ((geo->raid_disks % geo->far_set_size) &&
 594                             (d > last_far_set_start)) {
 595                                 d -= last_far_set_start;
 596                                 d %= last_far_set_size;
 597                                 d += last_far_set_start;
 598                         } else {
 599                                 d %= geo->far_set_size;
 600                                 d += geo->far_set_size * set;
 601                         }
 602                         s += geo->stride;
 603                         r10bio->devs[slot].devnum = d;
 604                         r10bio->devs[slot].addr = s;
 605                         slot++;
 606                 }
 607                 dev++;
 608                 if (dev >= geo->raid_disks) {
 609                         dev = 0;
 610                         sector += (geo->chunk_mask + 1);
 611                 }
 612         }
 613 }
 614
 615 static void raid10_find_phys(struct r10conf *conf, struct r10bio *r10bio)
 616 {
 617         struct geom *geo = &conf->geo;
 618
 619         if (conf->reshape_progress != MaxSector &&
 620             ((r10bio->sector >= conf->reshape_progress) !=
 621              conf->mddev->reshape_backwards)) {
 622                 set_bit(R10BIO_Previous, &r10bio->state);
 623                 geo = &conf->prev;
 624         } else
 625                 clear_bit(R10BIO_Previous, &r10bio->state);
 626
 627         __raid10_find_phys(geo, r10bio);
 628 }
 629
 630 static sector_t raid10_find_virt(struct r10conf *conf, sector_t sector, int dev)
 631 {
 632         sector_t offset, chunk, vchunk;
 633         /* Never use conf->prev as this is only called during resync
 634          * or recovery, so reshape isn't happening
 635          */
 636         struct geom *geo = &conf->geo;
 637         int far_set_start = (dev / geo->far_set_size) * geo->far_set_size;
 638         int far_set_size = geo->far_set_size;
 639         int last_far_set_start;
 640
 641         if (geo->raid_disks % geo->far_set_size) {
 642                 last_far_set_start = (geo->raid_disks / geo->far_set_size) - 1;
 643                 last_far_set_start *= geo->far_set_size;
 644
 645                 if (dev >= last_far_set_start) {
 646                         far_set_size = geo->far_set_size;
 647                         far_set_size += (geo->raid_disks % geo->far_set_size);
 648                         far_set_start = last_far_set_start;
 649                 }
 650         }
 651
 652         offset = sector & geo->chunk_mask;
 653         if (geo->far_offset) {
 654                 int fc;
 655                 chunk = sector >> geo->chunk_shift;
 656                 fc = sector_div(chunk, geo->far_copies);
 657                 dev -= fc * geo->near_copies;
 658                 if (dev < far_set_start)
 659                         dev += far_set_size;
 660         } else {
 661                 while (sector >= geo->stride) {
 662                         sector -= geo->stride;
 663                         if (dev < (geo->near_copies + far_set_start))
 664                                 dev += far_set_size - geo->near_copies;
 665                         else
 666                                 dev -= geo->near_copies;
 667                 }
 668                 chunk = sector >> geo->chunk_shift;
 669         }
 670         vchunk = chunk * geo->raid_disks + dev;
 671         sector_div(vchunk, geo->near_copies);
 672         return (vchunk << geo->chunk_shift) + offset;
 673 }
 674
 675 /*
 676  * This routine returns the disk from which the requested read should
 677  * be done. There is a per-array 'next expected sequential IO' sector
 678  * number - if this matches on the next IO then we use the last disk.
 679  * There is also a per-disk 'last know head position' sector that is
 680  * maintained from IRQ contexts, both the normal and the resync IO
 681  * completion handlers update this position correctly. If there is no
 682  * perfect sequential match then we pick the disk whose head is closest.
 683  *
 684  * If there are 2 mirrors in the same 2 devices, performance degrades
 685  * because position is mirror, not device based.
 686  *
 687  * The rdev for the device selected will have nr_pending incremented.
 688  */
 689
 690 /*
 691  * FIXME: possibly should rethink readbalancing and do it differently
 692  * depending on near_copies / far_copies geometry.
 693  */
 694 static struct md_rdev *read_balance(struct r10conf *conf,
 695                                     struct r10bio *r10_bio,
 696                                     int *max_sectors)
 697 {
 698         const sector_t this_sector = r10_bio->sector;
 699         int disk, slot;
 700         int sectors = r10_bio->sectors;
 701         int best_good_sectors;
 702         sector_t new_distance, best_dist;
 703         struct md_rdev *best_rdev, *rdev = NULL;
 704         int do_balance;
 705         int best_slot;
 706         struct geom *geo = &conf->geo;
 707
 708         raid10_find_phys(conf, r10_bio);
 709         rcu_read_lock();
 710 retry:
 711         sectors = r10_bio->sectors;
 712         best_slot = -1;
 713         best_rdev = NULL;
 714         best_dist = MaxSector;
 715         best_good_sectors = 0;
 716         do_balance = 1;
 717         /*
 718          * Check if we can balance. We can balance on the whole
 719          * device if no resync is going on (recovery is ok), or below
 720          * the resync window. We take the first readable disk when
 721          * above the resync window.
 722          */
 723         if (conf->mddev->recovery_cp < MaxSector
 724             && (this_sector + sectors >= conf->next_resync))
 725                 do_balance = 0;
 726
 727         for (slot = 0; slot < conf->copies ; slot++) {
 728                 sector_t first_bad;
 729                 int bad_sectors;
 730                 sector_t dev_sector;
 731
 732                 if (r10_bio->devs[slot].bio == IO_BLOCKED)
 733                         continue;
 734                 disk = r10_bio->devs[slot].devnum;
 735                 rdev = rcu_dereference(conf->mirrors[disk].replacement);
 736                 if (rdev == NULL || test_bit(Faulty, &rdev->flags) ||
 737                     r10_bio->devs[slot].addr + sectors > rdev->recovery_offset)
 738                         rdev = rcu_dereference(conf->mirrors[disk].rdev);
 739                 if (rdev == NULL ||
 740                     test_bit(Faulty, &rdev->flags))
 741                         continue;
 742                 if (!test_bit(In_sync, &rdev->flags) &&
 743                     r10_bio->devs[slot].addr + sectors > rdev->recovery_offset)
 744                         continue;
 745
 746                 dev_sector = r10_bio->devs[slot].addr;
 747                 if (is_badblock(rdev, dev_sector, sectors,
 748                                 &first_bad, &bad_sectors)) {
 749                         if (best_dist < MaxSector)
 750                                 /* Already have a better slot */
 751                                 continue;
 752                         if (first_bad <= dev_sector) {
 753                                 /* Cannot read here.  If this is the
 754                                  * 'primary' device, then we must not read
 755                                  * beyond 'bad_sectors' from another device.
 756                                  */
 757                                 bad_sectors -= (dev_sector - first_bad);
 758                                 if (!do_balance && sectors > bad_sectors)
 759                                         sectors = bad_sectors;
 760                                 if (best_good_sectors > sectors)
 761                                         best_good_sectors = sectors;
 762                         } else {
 763                                 sector_t good_sectors =
 764                                         first_bad - dev_sector;
 765                                 if (good_sectors > best_good_sectors) {
 766                                         best_good_sectors = good_sectors;
 767                                         best_slot = slot;
 768                                         best_rdev = rdev;
 769                                 }
 770                                 if (!do_balance)
 771                                         /* Must read from here */
 772                                         break;
 773                         }
 774                         continue;
 775                 } else
 776                         best_good_sectors = sectors;
 777
 778                 if (!do_balance)
 779                         break;
 780
 781                 /* This optimisation is debatable, and completely destroys
 782                  * sequential read speed for 'far copies' arrays.  So only
 783                  * keep it for 'near' arrays, and review those later.
 784                  */
 785                 if (geo->near_copies > 1 && !atomic_read(&rdev->nr_pending))
 786                         break;
 787
 788                 /* for far > 1 always use the lowest address */
 789                 if (geo->far_copies > 1)
 790                         new_distance = r10_bio->devs[slot].addr;
 791                 else
 792                         new_distance = abs(r10_bio->devs[slot].addr -
 793                                            conf->mirrors[disk].head_position);
 794                 if (new_distance < best_dist) {
 795                         best_dist = new_distance;
 796                         best_slot = slot;
 797                         best_rdev = rdev;
 798                 }
 799         }
 800         if (slot >= conf->copies) {
 801                 slot = best_slot;
 802                 rdev = best_rdev;
 803         }
 804
 805         if (slot >= 0) {
 806                 atomic_inc(&rdev->nr_pending);
 807                 if (test_bit(Faulty, &rdev->flags)) {
 808                         /* Cannot risk returning a device that failed
 809                          * before we inc'ed nr_pending
 810                          */
 811                         rdev_dec_pending(rdev, conf->mddev);
 812                         goto retry;
 813                 }
 814                 r10_bio->read_slot = slot;
 815         } else
 816                 rdev = NULL;
 817         rcu_read_unlock();
 818         *max_sectors = best_good_sectors;
 819
 820         return rdev;
 821 }
 822
 823 static int raid10_congested(struct mddev *mddev, int bits)
 824 {
 825         struct r10conf *conf = mddev->private;
 826         int i, ret = 0;
 827
 828         if ((bits & (1 << WB_async_congested)) &&
 829             conf->pending_count >= max_queued_requests)
 830                 return 1;
 831
 832         rcu_read_lock();
 833         for (i = 0;
 834              (i < conf->geo.raid_disks || i < conf->prev.raid_disks)
 835                      && ret == 0;
 836              i++) {
 837                 struct md_rdev *rdev = rcu_dereference(conf->mirrors[i].rdev);
 838                 if (rdev && !test_bit(Faulty, &rdev->flags)) {
 839                         struct request_queue *q = bdev_get_queue(rdev->bdev);
 840
 841                         ret |= bdi_congested(&q->backing_dev_info, bits);
 842                 }
 843         }
 844         rcu_read_unlock();
 845         return ret;
 846 }
 847
 848 static void flush_pending_writes(struct r10conf *conf)
 849 {
 850         /* Any writes that have been queued but are awaiting
 851          * bitmap updates get flushed here.
 852          */
 853         spin_lock_irq(&conf->device_lock);
 854
 855         if (conf->pending_bio_list.head) {
 856                 struct bio *bio;
 857                 bio = bio_list_get(&conf->pending_bio_list);
 858                 conf->pending_count = 0;
 859                 spin_unlock_irq(&conf->device_lock);
 860                 /* flush any pending bitmap writes to disk
 861                  * before proceeding w/ I/O */
 862                 bitmap_unplug(conf->mddev->bitmap);
 863                 wake_up(&conf->wait_barrier);
 864
 865                 while (bio) { /* submit pending writes */
 866                         struct bio *next = bio->bi_next;
 867                         bio->bi_next = NULL;
 868                         if (unlikely((bio->bi_rw & REQ_DISCARD) &&
 869                             !blk_queue_discard(bdev_get_queue(bio->bi_bdev))))
 870                                 /* Just ignore it */
 871                                 bio_endio(bio);
 872                         else
 873                                 generic_make_request(bio);
 874                         bio = next;
 875                 }
 876         } else
 877                 spin_unlock_irq(&conf->device_lock);
 878 }
 879
 880 /* Barriers....
 881  * Sometimes we need to suspend IO while we do something else,
 882  * either some resync/recovery, or reconfigure the array.
 883  * To do this we raise a 'barrier'.
 884  * The 'barrier' is a counter that can be raised multiple times
 885  * to count how many activities are happening which preclude
 886  * normal IO.
 887  * We can only raise the barrier if there is no pending IO.
 888  * i.e. if nr_pending == 0.
 889  * We choose only to raise the barrier if no-one is waiting for the
 890  * barrier to go down.  This means that as soon as an IO request
 891  * is ready, no other operations which require a barrier will start
 892  * until the IO request has had a chance.
 893  *
 894  * So: regular IO calls 'wait_barrier'.  When that returns there
 895  *    is no backgroup IO happening,  It must arrange to call
 896  *    allow_barrier when it has finished its IO.
 897  * backgroup IO calls must call raise_barrier.  Once that returns
 898  *    there is no normal IO happeing.  It must arrange to call
 899  *    lower_barrier when the particular background IO completes.
 900  */
 901
 902 static void raise_barrier(struct r10conf *conf, int force)
 903 {
 904         BUG_ON(force && !conf->barrier);
 905         spin_lock_irq(&conf->resync_lock);
 906
 907         /* Wait until no block IO is waiting (unless 'force') */
 908         wait_event_lock_irq(conf->wait_barrier, force || !conf->nr_waiting,
 909                             conf->resync_lock);
 910
 911         /* block any new IO from starting */
 912         conf->barrier++;
 913
 914         /* Now wait for all pending IO to complete */
 915         wait_event_lock_irq(conf->wait_barrier,
 916                             !conf->nr_pending && conf->barrier < RESYNC_DEPTH,
 917                             conf->resync_lock);
 918
 919         spin_unlock_irq(&conf->resync_lock);
 920 }
 921
 922 static void lower_barrier(struct r10conf *conf)
 923 {
 924         unsigned long flags;
 925         spin_lock_irqsave(&conf->resync_lock, flags);
 926         conf->barrier--;
 927         spin_unlock_irqrestore(&conf->resync_lock, flags);
 928         wake_up(&conf->wait_barrier);
 929 }
 930
 931 static void wait_barrier(struct r10conf *conf)
 932 {
 933         spin_lock_irq(&conf->resync_lock);
 934         if (conf->barrier) {
 935                 conf->nr_waiting++;
 936                 /* Wait for the barrier to drop.
 937                  * However if there are already pending
 938                  * requests (preventing the barrier from
 939                  * rising completely), and the
 940                  * pre-process bio queue isn't empty,
 941                  * then don't wait, as we need to empty
 942                  * that queue to get the nr_pending
 943                  * count down.
 944                  */
 945                 wait_event_lock_irq(conf->wait_barrier,
 946                                     !conf->barrier ||
 947                                     (conf->nr_pending &&
 948                                      current->bio_list &&
 949                                      !bio_list_empty(current->bio_list)),
 950                                     conf->resync_lock);
 951                 conf->nr_waiting--;
 952         }
 953         conf->nr_pending++;
 954         spin_unlock_irq(&conf->resync_lock);
 955 }
 956
 957 static void allow_barrier(struct r10conf *conf)
 958 {
 959         unsigned long flags;
 960         spin_lock_irqsave(&conf->resync_lock, flags);
 961         conf->nr_pending--;
 962         spin_unlock_irqrestore(&conf->resync_lock, flags);
 963         wake_up(&conf->wait_barrier);
 964 }
 965
 966 static void freeze_array(struct r10conf *conf, int extra)
 967 {
 968         /* stop syncio and normal IO and wait for everything to
 969          * go quiet.
 970          * We increment barrier and nr_waiting, and then
 971          * wait until nr_pending match nr_queued+extra
 972          * This is called in the context of one normal IO request
 973          * that has failed. Thus any sync request that might be pending
 974          * will be blocked by nr_pending, and we need to wait for
 975          * pending IO requests to complete or be queued for re-try.
 976          * Thus the number queued (nr_queued) plus this request (extra)
 977          * must match the number of pending IOs (nr_pending) before
 978          * we continue.
 979          */
 980         spin_lock_irq(&conf->resync_lock);
 981         conf->barrier++;
 982         conf->nr_waiting++;
 983         wait_event_lock_irq_cmd(conf->wait_barrier,
 984                                 conf->nr_pending == conf->nr_queued+extra,
 985                                 conf->resync_lock,
 986                                 flush_pending_writes(conf));
 987
 988         spin_unlock_irq(&conf->resync_lock);
 989 }
 990
 991 static void unfreeze_array(struct r10conf *conf)
 992 {
 993         /* reverse the effect of the freeze */
 994         spin_lock_irq(&conf->resync_lock);
 995         conf->barrier--;
 996         conf->nr_waiting--;
 997         wake_up(&conf->wait_barrier);
 998         spin_unlock_irq(&conf->resync_lock);
 999 }
1000
1001 static sector_t choose_data_offset(struct r10bio *r10_bio,
1002                                    struct md_rdev *rdev)
1003 {
1004         if (!test_bit(MD_RECOVERY_RESHAPE, &rdev->mddev->recovery) ||
1005             test_bit(R10BIO_Previous, &r10_bio->state))
1006                 return rdev->data_offset;
1007         else
1008                 return rdev->new_data_offset;
1009 }
1010
1011 struct raid10_plug_cb {
1012         struct blk_plug_cb      cb;
1013         struct bio_list         pending;
1014         int                     pending_cnt;
1015 };
1016
1017 static void raid10_unplug(struct blk_plug_cb *cb, bool from_schedule)
1018 {
1019         struct raid10_plug_cb *plug = container_of(cb, struct raid10_plug_cb,
1020                                                    cb);
1021         struct mddev *mddev = plug->cb.data;
1022         struct r10conf *conf = mddev->private;
1023         struct bio *bio;
1024
1025         if (from_schedule || current->bio_list) {
1026                 spin_lock_irq(&conf->device_lock);
1027                 bio_list_merge(&conf->pending_bio_list, &plug->pending);
1028                 conf->pending_count += plug->pending_cnt;
1029                 spin_unlock_irq(&conf->device_lock);
1030                 wake_up(&conf->wait_barrier);
1031                 md_wakeup_thread(mddev->thread);
1032                 kfree(plug);
1033                 return;
1034         }
1035
1036         /* we aren't scheduling, so we can do the write-out directly. */
1037         bio = bio_list_get(&plug->pending);
1038         bitmap_unplug(mddev->bitmap);
1039         wake_up(&conf->wait_barrier);
1040
1041         while (bio) { /* submit pending writes */
1042                 struct bio *next = bio->bi_next;
1043                 bio->bi_next = NULL;
1044                 if (unlikely((bio->bi_rw & REQ_DISCARD) &&
1045                     !blk_queue_discard(bdev_get_queue(bio->bi_bdev))))
1046                         /* Just ignore it */
1047                         bio_endio(bio);
1048                 else
1049                         generic_make_request(bio);
1050                 bio = next;
1051         }
1052         kfree(plug);
1053 }
1054
1055 static void __make_request(struct mddev *mddev, struct bio *bio)
1056 {
1057         struct r10conf *conf = mddev->private;
1058         struct r10bio *r10_bio;
1059         struct bio *read_bio;
1060         int i;
1061         const int rw = bio_data_dir(bio);
1062         const unsigned long do_sync = (bio->bi_rw & REQ_SYNC);
1063         const unsigned long do_fua = (bio->bi_rw & REQ_FUA);
1064         const unsigned long do_discard = (bio->bi_rw
1065                                           & (REQ_DISCARD | REQ_SECURE));
1066         const unsigned long do_same = (bio->bi_rw & REQ_WRITE_SAME);
1067         unsigned long flags;
1068         struct md_rdev *blocked_rdev;
1069         struct blk_plug_cb *cb;
1070         struct raid10_plug_cb *plug = NULL;
1071         int sectors_handled;
1072         int max_sectors;
1073         int sectors;
1074
1075         /*
1076          * Register the new request and wait if the reconstruction
1077          * thread has put up a bar for new requests.
1078          * Continue immediately if no resync is active currently.
1079          */
1080         wait_barrier(conf);
1081
1082         sectors = bio_sectors(bio);
1083         while (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery) &&
1084             bio->bi_iter.bi_sector < conf->reshape_progress &&
1085             bio->bi_iter.bi_sector + sectors > conf->reshape_progress) {
1086                 /* IO spans the reshape position.  Need to wait for
1087                  * reshape to pass
1088                  */
1089                 allow_barrier(conf);
1090                 wait_event(conf->wait_barrier,
1091                            conf->reshape_progress <= bio->bi_iter.bi_sector ||
1092                            conf->reshape_progress >= bio->bi_iter.bi_sector +
1093                            sectors);
1094                 wait_barrier(conf);
1095         }
1096         if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery) &&
1097             bio_data_dir(bio) == WRITE &&
1098             (mddev->reshape_backwards
1099              ? (bio->bi_iter.bi_sector < conf->reshape_safe &&
1100                 bio->bi_iter.bi_sector + sectors > conf->reshape_progress)
1101              : (bio->bi_iter.bi_sector + sectors > conf->reshape_safe &&
1102                 bio->bi_iter.bi_sector < conf->reshape_progress))) {
1103                 /* Need to update reshape_position in metadata */
1104                 mddev->reshape_position = conf->reshape_progress;
1105                 set_mask_bits(&mddev->flags, 0,
1106                               BIT(MD_CHANGE_DEVS) | BIT(MD_CHANGE_PENDING));
1107                 md_wakeup_thread(mddev->thread);
1108                 wait_event(mddev->sb_wait,
1109                            !test_bit(MD_CHANGE_PENDING, &mddev->flags));
1110
1111                 conf->reshape_safe = mddev->reshape_position;
1112         }
1113
1114         r10_bio = mempool_alloc(conf->r10bio_pool, GFP_NOIO);
1115
1116         r10_bio->master_bio = bio;
1117         r10_bio->sectors = sectors;
1118
1119         r10_bio->mddev = mddev;
1120         r10_bio->sector = bio->bi_iter.bi_sector;
1121         r10_bio->state = 0;
1122
1123         /* We might need to issue multiple reads to different
1124          * devices if there are bad blocks around, so we keep
1125          * track of the number of reads in bio->bi_phys_segments.
1126          * If this is 0, there is only one r10_bio and no locking
1127          * will be needed when the request completes.  If it is
1128          * non-zero, then it is the number of not-completed requests.
1129          */
1130         bio->bi_phys_segments = 0;
1131         bio_clear_flag(bio, BIO_SEG_VALID);
1132
1133         if (rw == READ) {
1134                 /*
1135                  * read balancing logic:
1136                  */
1137                 struct md_rdev *rdev;
1138                 int slot;
1139
1140 read_again:
1141                 rdev = read_balance(conf, r10_bio, &max_sectors);
1142                 if (!rdev) {
1143                         raid_end_bio_io(r10_bio);
1144                         return;
1145                 }
1146                 slot = r10_bio->read_slot;
1147
1148                 read_bio = bio_clone_mddev(bio, GFP_NOIO, mddev);
1149                 bio_trim(read_bio, r10_bio->sector - bio->bi_iter.bi_sector,
1150                          max_sectors);
1151
1152                 r10_bio->devs[slot].bio = read_bio;
1153                 r10_bio->devs[slot].rdev = rdev;
1154
1155                 read_bio->bi_iter.bi_sector = r10_bio->devs[slot].addr +
1156                         choose_data_offset(r10_bio, rdev);
1157                 read_bio->bi_bdev = rdev->bdev;
1158                 read_bio->bi_end_io = raid10_end_read_request;
1159                 read_bio->bi_rw = READ | do_sync;
1160                 read_bio->bi_private = r10_bio;
1161
1162                 if (max_sectors < r10_bio->sectors) {
1163                         /* Could not read all from this device, so we will
1164                          * need another r10_bio.
1165                          */
1166                         sectors_handled = (r10_bio->sector + max_sectors
1167                                            - bio->bi_iter.bi_sector);
1168                         r10_bio->sectors = max_sectors;
1169                         spin_lock_irq(&conf->device_lock);
1170                         if (bio->bi_phys_segments == 0)
1171                                 bio->bi_phys_segments = 2;
1172                         else
1173                                 bio->bi_phys_segments++;
1174                         spin_unlock_irq(&conf->device_lock);
1175                         /* Cannot call generic_make_request directly
1176                          * as that will be queued in __generic_make_request
1177                          * and subsequent mempool_alloc might block
1178                          * waiting for it.  so hand bio over to raid10d.
1179                          */
1180                         reschedule_retry(r10_bio);
1181
1182                         r10_bio = mempool_alloc(conf->r10bio_pool, GFP_NOIO);
1183
1184                         r10_bio->master_bio = bio;
1185                         r10_bio->sectors = bio_sectors(bio) - sectors_handled;
1186                         r10_bio->state = 0;
1187                         r10_bio->mddev = mddev;
1188                         r10_bio->sector = bio->bi_iter.bi_sector +
1189                                 sectors_handled;
1190                         goto read_again;
1191                 } else
1192                         generic_make_request(read_bio);
1193                 return;
1194         }
1195
1196         /*
1197          * WRITE:
1198          */
1199         if (conf->pending_count >= max_queued_requests) {
1200                 md_wakeup_thread(mddev->thread);
1201                 wait_event(conf->wait_barrier,
1202                            conf->pending_count < max_queued_requests);
1203         }
1204         /* first select target devices under rcu_lock and
1205          * inc refcount on their rdev.  Record them by setting
1206          * bios[x] to bio
1207          * If there are known/acknowledged bad blocks on any device
1208          * on which we have seen a write error, we want to avoid
1209          * writing to those blocks.  This potentially requires several
1210          * writes to write around the bad blocks.  Each set of writes
1211          * gets its own r10_bio with a set of bios attached.  The number
1212          * of r10_bios is recored in bio->bi_phys_segments just as with
1213          * the read case.
1214          */
1215
1216         r10_bio->read_slot = -1; /* make sure repl_bio gets freed */
1217         raid10_find_phys(conf, r10_bio);
1218 retry_write:
1219         blocked_rdev = NULL;
1220         rcu_read_lock();
1221         max_sectors = r10_bio->sectors;
1222
1223         for (i = 0;  i < conf->copies; i++) {
1224                 int d = r10_bio->devs[i].devnum;
1225                 struct md_rdev *rdev = rcu_dereference(conf->mirrors[d].rdev);
1226                 struct md_rdev *rrdev = rcu_dereference(
1227                         conf->mirrors[d].replacement);
1228                 if (rdev == rrdev)
1229                         rrdev = NULL;
1230                 if (rdev && unlikely(test_bit(Blocked, &rdev->flags))) {
1231                         atomic_inc(&rdev->nr_pending);
1232                         blocked_rdev = rdev;
1233                         break;
1234                 }
1235                 if (rrdev && unlikely(test_bit(Blocked, &rrdev->flags))) {
1236                         atomic_inc(&rrdev->nr_pending);
1237                         blocked_rdev = rrdev;
1238                         break;
1239                 }
1240                 if (rdev && (test_bit(Faulty, &rdev->flags)))
1241                         rdev = NULL;
1242                 if (rrdev && (test_bit(Faulty, &rrdev->flags)))
1243                         rrdev = NULL;
1244
1245                 r10_bio->devs[i].bio = NULL;
1246                 r10_bio->devs[i].repl_bio = NULL;
1247
1248                 if (!rdev && !rrdev) {
1249                         set_bit(R10BIO_Degraded, &r10_bio->state);
1250                         continue;
1251                 }
1252                 if (rdev && test_bit(WriteErrorSeen, &rdev->flags)) {
1253                         sector_t first_bad;
1254                         sector_t dev_sector = r10_bio->devs[i].addr;
1255                         int bad_sectors;
1256                         int is_bad;
1257
1258                         is_bad = is_badblock(rdev, dev_sector,
1259                                              max_sectors,
1260                                              &first_bad, &bad_sectors);
1261                         if (is_bad < 0) {
1262                                 /* Mustn't write here until the bad block
1263                                  * is acknowledged
1264                                  */
1265                                 atomic_inc(&rdev->nr_pending);
1266                                 set_bit(BlockedBadBlocks, &rdev->flags);
1267                                 blocked_rdev = rdev;
1268                                 break;
1269                         }
1270                         if (is_bad && first_bad <= dev_sector) {
1271                                 /* Cannot write here at all */
1272                                 bad_sectors -= (dev_sector - first_bad);
1273                                 if (bad_sectors < max_sectors)
1274                                         /* Mustn't write more than bad_sectors
1275                                          * to other devices yet
1276                                          */
1277                                         max_sectors = bad_sectors;
1278                                 /* We don't set R10BIO_Degraded as that
1279                                  * only applies if the disk is missing,
1280                                  * so it might be re-added, and we want to
1281                                  * know to recover this chunk.
1282                                  * In this case the device is here, and the
1283                                  * fact that this chunk is not in-sync is
1284                                  * recorded in the bad block log.
1285                                  */
1286                                 continue;
1287                         }
1288                         if (is_bad) {
1289                                 int good_sectors = first_bad - dev_sector;
1290                                 if (good_sectors < max_sectors)
1291                                         max_sectors = good_sectors;
1292                         }
1293                 }
1294                 if (rdev) {
1295                         r10_bio->devs[i].bio = bio;
1296                         atomic_inc(&rdev->nr_pending);
1297                 }
1298                 if (rrdev) {
1299                         r10_bio->devs[i].repl_bio = bio;
1300                         atomic_inc(&rrdev->nr_pending);
1301                 }
1302         }
1303         rcu_read_unlock();
1304
1305         if (unlikely(blocked_rdev)) {
1306                 /* Have to wait for this device to get unblocked, then retry */
1307                 int j;
1308                 int d;
1309
1310                 for (j = 0; j < i; j++) {
1311                         if (r10_bio->devs[j].bio) {
1312                                 d = r10_bio->devs[j].devnum;
1313                                 rdev_dec_pending(conf->mirrors[d].rdev, mddev);
1314                         }
1315                         if (r10_bio->devs[j].repl_bio) {
1316                                 struct md_rdev *rdev;
1317                                 d = r10_bio->devs[j].devnum;
1318                                 rdev = conf->mirrors[d].replacement;
1319                                 if (!rdev) {
1320                                         /* Race with remove_disk */
1321                                         smp_mb();
1322                                         rdev = conf->mirrors[d].rdev;
1323                                 }
1324                                 rdev_dec_pending(rdev, mddev);
1325                         }
1326                 }
1327                 allow_barrier(conf);
1328                 md_wait_for_blocked_rdev(blocked_rdev, mddev);
1329                 wait_barrier(conf);
1330                 goto retry_write;
1331         }
1332
1333         if (max_sectors < r10_bio->sectors) {
1334                 /* We are splitting this into multiple parts, so
1335                  * we need to prepare for allocating another r10_bio.
1336                  */
1337                 r10_bio->sectors = max_sectors;
1338                 spin_lock_irq(&conf->device_lock);
1339                 if (bio->bi_phys_segments == 0)
1340                         bio->bi_phys_segments = 2;
1341                 else
1342                         bio->bi_phys_segments++;
1343                 spin_unlock_irq(&conf->device_lock);
1344         }
1345         sectors_handled = r10_bio->sector + max_sectors -
1346                 bio->bi_iter.bi_sector;
1347
1348         atomic_set(&r10_bio->remaining, 1);
1349         bitmap_startwrite(mddev->bitmap, r10_bio->sector, r10_bio->sectors, 0);
1350
1351         for (i = 0; i < conf->copies; i++) {
1352                 struct bio *mbio;
1353                 int d = r10_bio->devs[i].devnum;
1354                 if (r10_bio->devs[i].bio) {
1355                         struct md_rdev *rdev = conf->mirrors[d].rdev;
1356                         mbio = bio_clone_mddev(bio, GFP_NOIO, mddev);
1357                         bio_trim(mbio, r10_bio->sector - bio->bi_iter.bi_sector,
1358                                  max_sectors);
1359                         r10_bio->devs[i].bio = mbio;
1360
1361                         mbio->bi_iter.bi_sector = (r10_bio->devs[i].addr+
1362                                            choose_data_offset(r10_bio,
1363                                                               rdev));
1364                         mbio->bi_bdev = rdev->bdev;
1365                         mbio->bi_end_io = raid10_end_write_request;
1366                         mbio->bi_rw =
1367                                 WRITE | do_sync | do_fua | do_discard | do_same;
1368                         mbio->bi_private = r10_bio;
1369
1370                         atomic_inc(&r10_bio->remaining);
1371
1372                         cb = blk_check_plugged(raid10_unplug, mddev,
1373                                                sizeof(*plug));
1374                         if (cb)
1375                                 plug = container_of(cb, struct raid10_plug_cb,
1376                                                     cb);
1377                         else
1378                                 plug = NULL;
1379                         spin_lock_irqsave(&conf->device_lock, flags);
1380                         if (plug) {
1381                                 bio_list_add(&plug->pending, mbio);
1382                                 plug->pending_cnt++;
1383                         } else {
1384                                 bio_list_add(&conf->pending_bio_list, mbio);
1385                                 conf->pending_count++;
1386                         }
1387                         spin_unlock_irqrestore(&conf->device_lock, flags);
1388                         if (!plug)
1389                                 md_wakeup_thread(mddev->thread);
1390                 }
1391
1392                 if (r10_bio->devs[i].repl_bio) {
1393                         struct md_rdev *rdev = conf->mirrors[d].replacement;
1394                         if (rdev == NULL) {
1395                                 /* Replacement just got moved to main 'rdev' */
1396                                 smp_mb();
1397                                 rdev = conf->mirrors[d].rdev;
1398                         }
1399                         mbio = bio_clone_mddev(bio, GFP_NOIO, mddev);
1400                         bio_trim(mbio, r10_bio->sector - bio->bi_iter.bi_sector,
1401                                  max_sectors);
1402                         r10_bio->devs[i].repl_bio = mbio;
1403
1404                         mbio->bi_iter.bi_sector = (r10_bio->devs[i].addr +
1405                                            choose_data_offset(
1406                                                    r10_bio, rdev));
1407                         mbio->bi_bdev = rdev->bdev;
1408                         mbio->bi_end_io = raid10_end_write_request;
1409                         mbio->bi_rw =
1410                                 WRITE | do_sync | do_fua | do_discard | do_same;
1411                         mbio->bi_private = r10_bio;
1412
1413                         atomic_inc(&r10_bio->remaining);
1414                         spin_lock_irqsave(&conf->device_lock, flags);
1415                         bio_list_add(&conf->pending_bio_list, mbio);
1416                         conf->pending_count++;
1417                         spin_unlock_irqrestore(&conf->device_lock, flags);
1418                         if (!mddev_check_plugged(mddev))
1419                                 md_wakeup_thread(mddev->thread);
1420                 }
1421         }
1422
1423         /* Don't remove the bias on 'remaining' (one_write_done) until
1424          * after checking if we need to go around again.
1425          */
1426
1427         if (sectors_handled < bio_sectors(bio)) {
1428                 one_write_done(r10_bio);
1429                 /* We need another r10_bio.  It has already been counted
1430                  * in bio->bi_phys_segments.
1431                  */
1432                 r10_bio = mempool_alloc(conf->r10bio_pool, GFP_NOIO);
1433
1434                 r10_bio->master_bio = bio;
1435                 r10_bio->sectors = bio_sectors(bio) - sectors_handled;
1436
1437                 r10_bio->mddev = mddev;
1438                 r10_bio->sector = bio->bi_iter.bi_sector + sectors_handled;
1439                 r10_bio->state = 0;
1440                 goto retry_write;
1441         }
1442         one_write_done(r10_bio);
1443 }
1444
1445 static void raid10_make_request(struct mddev *mddev, struct bio *bio)
1446 {
1447         struct r10conf *conf = mddev->private;
1448         sector_t chunk_mask = (conf->geo.chunk_mask & conf->prev.chunk_mask);
1449         int chunk_sects = chunk_mask + 1;
1450
1451         struct bio *split;
1452
1453         if (unlikely(bio->bi_rw & REQ_FLUSH)) {
1454                 md_flush_request(mddev, bio);
1455                 return;
1456         }
1457
1458         md_write_start(mddev, bio);
1459
1460         do {
1461
1462                 /*
1463                  * If this request crosses a chunk boundary, we need to split
1464                  * it.
1465                  */
1466                 if (unlikely((bio->bi_iter.bi_sector & chunk_mask) +
1467                              bio_sectors(bio) > chunk_sects
1468                              && (conf->geo.near_copies < conf->geo.raid_disks
1469                                  || conf->prev.near_copies <
1470                                  conf->prev.raid_disks))) {
1471                         split = bio_split(bio, chunk_sects -
1472                                           (bio->bi_iter.bi_sector &
1473                                            (chunk_sects - 1)),
1474                                           GFP_NOIO, fs_bio_set);
1475                         bio_chain(split, bio);
1476                 } else {
1477                         split = bio;
1478                 }
1479
1480                 __make_request(mddev, split);
1481         } while (split != bio);
1482
1483         /* In case raid10d snuck in to freeze_array */
1484         wake_up(&conf->wait_barrier);
1485 }
1486
1487 static void raid10_status(struct seq_file *seq, struct mddev *mddev)
1488 {
1489         struct r10conf *conf = mddev->private;
1490         int i;
1491
1492         if (conf->geo.near_copies < conf->geo.raid_disks)
1493                 seq_printf(seq, " %dK chunks", mddev->chunk_sectors / 2);
1494         if (conf->geo.near_copies > 1)
1495                 seq_printf(seq, " %d near-copies", conf->geo.near_copies);
1496         if (conf->geo.far_copies > 1) {
1497                 if (conf->geo.far_offset)
1498                         seq_printf(seq, " %d offset-copies", conf->geo.far_copies);
1499                 else
1500                         seq_printf(seq, " %d far-copies", conf->geo.far_copies);
1501                 if (conf->geo.far_set_size != conf->geo.raid_disks)
1502                         seq_printf(seq, " %d devices per set", conf->geo.far_set_size);
1503         }
1504         seq_printf(seq, " [%d/%d] [", conf->geo.raid_disks,
1505                                         conf->geo.raid_disks - mddev->degraded);
1506         for (i = 0; i < conf->geo.raid_disks; i++)
1507                 seq_printf(seq, "%s",
1508                               conf->mirrors[i].rdev &&
1509                               test_bit(In_sync, &conf->mirrors[i].rdev->flags) ? "U" : "_");
1510         seq_printf(seq, "]");
1511 }
1512
1513 /* check if there are enough drives for
1514  * every block to appear on atleast one.
1515  * Don't consider the device numbered 'ignore'
1516  * as we might be about to remove it.
1517  */
1518 static int _enough(struct r10conf *conf, int previous, int ignore)
1519 {
1520         int first = 0;
1521         int has_enough = 0;
1522         int disks, ncopies;
1523         if (previous) {
1524                 disks = conf->prev.raid_disks;
1525                 ncopies = conf->prev.near_copies;
1526         } else {
1527                 disks = conf->geo.raid_disks;
1528                 ncopies = conf->geo.near_copies;
1529         }
1530
1531         rcu_read_lock();
1532         do {
1533                 int n = conf->copies;
1534                 int cnt = 0;
1535                 int this = first;
1536                 while (n--) {
1537                         struct md_rdev *rdev;
1538                         if (this != ignore &&
1539                             (rdev = rcu_dereference(conf->mirrors[this].rdev)) &&
1540                             test_bit(In_sync, &rdev->flags))
1541                                 cnt++;
1542                         this = (this+1) % disks;
1543                 }
1544                 if (cnt == 0)
1545                         goto out;
1546                 first = (first + ncopies) % disks;
1547         } while (first != 0);
1548         has_enough = 1;
1549 out:
1550         rcu_read_unlock();
1551         return has_enough;
1552 }
1553
1554 static int enough(struct r10conf *conf, int ignore)
1555 {
1556         /* when calling 'enough', both 'prev' and 'geo' must
1557          * be stable.
1558          * This is ensured if ->reconfig_mutex or ->device_lock
1559          * is held.
1560          */
1561         return _enough(conf, 0, ignore) &&
1562                 _enough(conf, 1, ignore);
1563 }
1564
1565 static void raid10_error(struct mddev *mddev, struct md_rdev *rdev)
1566 {
1567         char b[BDEVNAME_SIZE];
1568         struct r10conf *conf = mddev->private;
1569         unsigned long flags;
1570
1571         /*
1572          * If it is not operational, then we have already marked it as dead
1573          * else if it is the last working disks, ignore the error, let the
1574          * next level up know.
1575          * else mark the drive as failed
1576          */
1577         spin_lock_irqsave(&conf->device_lock, flags);
1578         if (test_bit(In_sync, &rdev->flags)
1579             && !enough(conf, rdev->raid_disk)) {
1580                 /*
1581                  * Don't fail the drive, just return an IO error.
1582                  */
1583                 spin_unlock_irqrestore(&conf->device_lock, flags);
1584                 return;
1585         }
1586         if (test_and_clear_bit(In_sync, &rdev->flags))
1587                 mddev->degraded++;
1588         /*
1589          * If recovery is running, make sure it aborts.
1590          */
1591         set_bit(MD_RECOVERY_INTR, &mddev->recovery);
1592         set_bit(Blocked, &rdev->flags);
1593         set_bit(Faulty, &rdev->flags);
1594         set_mask_bits(&mddev->flags, 0,
1595                       BIT(MD_CHANGE_DEVS) | BIT(MD_CHANGE_PENDING));
1596         spin_unlock_irqrestore(&conf->device_lock, flags);
1597         printk(KERN_ALERT
1598                "md/raid10:%s: Disk failure on %s, disabling device.\n"
1599                "md/raid10:%s: Operation continuing on %d devices.\n",
1600                mdname(mddev), bdevname(rdev->bdev, b),
1601                mdname(mddev), conf->geo.raid_disks - mddev->degraded);
1602 }
1603
1604 static void print_conf(struct r10conf *conf)
1605 {
1606         int i;
1607         struct raid10_info *tmp;
1608
1609         printk(KERN_DEBUG "RAID10 conf printout:\n");
1610         if (!conf) {
1611                 printk(KERN_DEBUG "(!conf)\n");
1612                 return;
1613         }
1614         printk(KERN_DEBUG " --- wd:%d rd:%d\n", conf->geo.raid_disks - conf->mddev->degraded,
1615                 conf->geo.raid_disks);
1616
1617         for (i = 0; i < conf->geo.raid_disks; i++) {
1618                 char b[BDEVNAME_SIZE];
1619                 tmp = conf->mirrors + i;
1620                 if (tmp->rdev)
1621                         printk(KERN_DEBUG " disk %d, wo:%d, o:%d, dev:%s\n",
1622                                 i, !test_bit(In_sync, &tmp->rdev->flags),
1623                                 !test_bit(Faulty, &tmp->rdev->flags),
1624                                 bdevname(tmp->rdev->bdev,b));
1625         }
1626 }
1627
1628 static void close_sync(struct r10conf *conf)
1629 {
1630         wait_barrier(conf);
1631         allow_barrier(conf);
1632
1633         mempool_destroy(conf->r10buf_pool);
1634         conf->r10buf_pool = NULL;
1635 }
1636
1637 static int raid10_spare_active(struct mddev *mddev)
1638 {
1639         int i;
1640         struct r10conf *conf = mddev->private;
1641         struct raid10_info *tmp;
1642         int count = 0;
1643         unsigned long flags;
1644
1645         /*
1646          * Find all non-in_sync disks within the RAID10 configuration
1647          * and mark them in_sync
1648          */
1649         for (i = 0; i < conf->geo.raid_disks; i++) {
1650                 tmp = conf->mirrors + i;
1651                 if (tmp->replacement
1652                     && tmp->replacement->recovery_offset == MaxSector
1653                     && !test_bit(Faulty, &tmp->replacement->flags)
1654                     && !test_and_set_bit(In_sync, &tmp->replacement->flags)) {
1655                         /* Replacement has just become active */
1656                         if (!tmp->rdev
1657                             || !test_and_clear_bit(In_sync, &tmp->rdev->flags))
1658                                 count++;
1659                         if (tmp->rdev) {
1660                                 /* Replaced device not technically faulty,
1661                                  * but we need to be sure it gets removed
1662                                  * and never re-added.
1663                                  */
1664                                 set_bit(Faulty, &tmp->rdev->flags);
1665                                 sysfs_notify_dirent_safe(
1666                                         tmp->rdev->sysfs_state);
1667                         }
1668                         sysfs_notify_dirent_safe(tmp->replacement->sysfs_state);
1669                 } else if (tmp->rdev
1670                            && tmp->rdev->recovery_offset == MaxSector
1671                            && !test_bit(Faulty, &tmp->rdev->flags)
1672                            && !test_and_set_bit(In_sync, &tmp->rdev->flags)) {
1673                         count++;
1674                         sysfs_notify_dirent_safe(tmp->rdev->sysfs_state);
1675                 }
1676         }
1677         spin_lock_irqsave(&conf->device_lock, flags);
1678         mddev->degraded -= count;
1679         spin_unlock_irqrestore(&conf->device_lock, flags);
1680
1681         print_conf(conf);
1682         return count;
1683 }
1684
1685 static int raid10_add_disk(struct mddev *mddev, struct md_rdev *rdev)
1686 {
1687         struct r10conf *conf = mddev->private;
1688         int err = -EEXIST;
1689         int mirror;
1690         int first = 0;
1691         int last = conf->geo.raid_disks - 1;
1692
1693         if (mddev->recovery_cp < MaxSector)
1694                 /* only hot-add to in-sync arrays, as recovery is
1695                  * very different from resync
1696                  */
1697                 return -EBUSY;
1698         if (rdev->saved_raid_disk < 0 && !_enough(conf, 1, -1))
1699                 return -EINVAL;
1700
1701         if (md_integrity_add_rdev(rdev, mddev))
1702                 return -ENXIO;
1703
1704         if (rdev->raid_disk >= 0)
1705                 first = last = rdev->raid_disk;
1706
1707         if (rdev->saved_raid_disk >= first &&
1708             conf->mirrors[rdev->saved_raid_disk].rdev == NULL)
1709                 mirror = rdev->saved_raid_disk;
1710         else
1711                 mirror = first;
1712         for ( ; mirror <= last ; mirror++) {
1713                 struct raid10_info *p = &conf->mirrors[mirror];
1714                 if (p->recovery_disabled == mddev->recovery_disabled)
1715                         continue;
1716                 if (p->rdev) {
1717                         if (!test_bit(WantReplacement, &p->rdev->flags) ||
1718                             p->replacement != NULL)
1719                                 continue;
1720                         clear_bit(In_sync, &rdev->flags);
1721                         set_bit(Replacement, &rdev->flags);
1722                         rdev->raid_disk = mirror;
1723                         err = 0;
1724                         if (mddev->gendisk)
1725                                 disk_stack_limits(mddev->gendisk, rdev->bdev,
1726                                                   rdev->data_offset << 9);
1727                         conf->fullsync = 1;
1728                         rcu_assign_pointer(p->replacement, rdev);
1729                         break;
1730                 }
1731
1732                 if (mddev->gendisk)
1733                         disk_stack_limits(mddev->gendisk, rdev->bdev,
1734                                           rdev->data_offset << 9);
1735
1736                 p->head_position = 0;
1737                 p->recovery_disabled = mddev->recovery_disabled - 1;
1738                 rdev->raid_disk = mirror;
1739                 err = 0;
1740                 if (rdev->saved_raid_disk != mirror)
1741                         conf->fullsync = 1;
1742                 rcu_assign_pointer(p->rdev, rdev);
1743                 break;
1744         }
1745         if (mddev->queue && blk_queue_discard(bdev_get_queue(rdev->bdev)))
1746                 queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, mddev->queue);
1747
1748         print_conf(conf);
1749         return err;
1750 }
1751
1752 static int raid10_remove_disk(struct mddev *mddev, struct md_rdev *rdev)
1753 {
1754         struct r10conf *conf = mddev->private;
1755         int err = 0;
1756         int number = rdev->raid_disk;
1757         struct md_rdev **rdevp;
1758         struct raid10_info *p = conf->mirrors + number;
1759
1760         print_conf(conf);
1761         if (rdev == p->rdev)
1762                 rdevp = &p->rdev;
1763         else if (rdev == p->replacement)
1764                 rdevp = &p->replacement;
1765         else
1766                 return 0;
1767
1768         if (test_bit(In_sync, &rdev->flags) ||
1769             atomic_read(&rdev->nr_pending)) {
1770                 err = -EBUSY;
1771                 goto abort;
1772         }
1773         /* Only remove faulty devices if recovery
1774          * is not possible.
1775          */
1776         if (!test_bit(Faulty, &rdev->flags) &&
1777             mddev->recovery_disabled != p->recovery_disabled &&
1778             (!p->replacement || p->replacement == rdev) &&
1779             number < conf->geo.raid_disks &&
1780             enough(conf, -1)) {
1781                 err = -EBUSY;
1782                 goto abort;
1783         }
1784         *rdevp = NULL;
1785         synchronize_rcu();
1786         if (atomic_read(&rdev->nr_pending)) {
1787                 /* lost the race, try later */
1788                 err = -EBUSY;
1789                 *rdevp = rdev;
1790                 goto abort;
1791         } else if (p->replacement) {
1792                 /* We must have just cleared 'rdev' */
1793                 p->rdev = p->replacement;
1794                 clear_bit(Replacement, &p->replacement->flags);
1795                 smp_mb(); /* Make sure other CPUs may see both as identical
1796                            * but will never see neither -- if they are careful.
1797                            */
1798                 p->replacement = NULL;
1799                 clear_bit(WantReplacement, &rdev->flags);
1800         } else
1801                 /* We might have just remove the Replacement as faulty
1802                  * Clear the flag just in case
1803                  */
1804                 clear_bit(WantReplacement, &rdev->flags);
1805
1806         err = md_integrity_register(mddev);
1807
1808 abort:
1809
1810         print_conf(conf);
1811         return err;
1812 }
1813
1814 static void end_sync_read(struct bio *bio)
1815 {
1816         struct r10bio *r10_bio = bio->bi_private;
1817         struct r10conf *conf = r10_bio->mddev->private;
1818         int d;
1819
1820         if (bio == r10_bio->master_bio) {
1821                 /* this is a reshape read */
1822                 d = r10_bio->read_slot; /* really the read dev */
1823         } else
1824                 d = find_bio_disk(conf, r10_bio, bio, NULL, NULL);
1825
1826         if (!bio->bi_error)
1827                 set_bit(R10BIO_Uptodate, &r10_bio->state);
1828         else
1829                 /* The write handler will notice the lack of
1830                  * R10BIO_Uptodate and record any errors etc
1831                  */
1832                 atomic_add(r10_bio->sectors,
1833                            &conf->mirrors[d].rdev->corrected_errors);
1834
1835         /* for reconstruct, we always reschedule after a read.
1836          * for resync, only after all reads
1837          */
1838         rdev_dec_pending(conf->mirrors[d].rdev, conf->mddev);
1839         if (test_bit(R10BIO_IsRecover, &r10_bio->state) ||
1840             atomic_dec_and_test(&r10_bio->remaining)) {
1841                 /* we have read all the blocks,
1842                  * do the comparison in process context in raid10d
1843                  */
1844                 reschedule_retry(r10_bio);
1845         }
1846 }
1847
1848 static void end_sync_request(struct r10bio *r10_bio)
1849 {
1850         struct mddev *mddev = r10_bio->mddev;
1851
1852         while (atomic_dec_and_test(&r10_bio->remaining)) {
1853                 if (r10_bio->master_bio == NULL) {
1854                         /* the primary of several recovery bios */
1855                         sector_t s = r10_bio->sectors;
1856                         if (test_bit(R10BIO_MadeGood, &r10_bio->state) ||
1857                             test_bit(R10BIO_WriteError, &r10_bio->state))
1858                                 reschedule_retry(r10_bio);
1859                         else
1860                                 put_buf(r10_bio);
1861                         md_done_sync(mddev, s, 1);
1862                         break;
1863                 } else {
1864                         struct r10bio *r10_bio2 = (struct r10bio *)r10_bio->master_bio;
1865                         if (test_bit(R10BIO_MadeGood, &r10_bio->state) ||
1866                             test_bit(R10BIO_WriteError, &r10_bio->state))
1867                                 reschedule_retry(r10_bio);
1868                         else
1869                                 put_buf(r10_bio);
1870                         r10_bio = r10_bio2;
1871                 }
1872         }
1873 }
1874
1875 static void end_sync_write(struct bio *bio)
1876 {
1877         struct r10bio *r10_bio = bio->bi_private;
1878         struct mddev *mddev = r10_bio->mddev;
1879         struct r10conf *conf = mddev->private;
1880         int d;
1881         sector_t first_bad;
1882         int bad_sectors;
1883         int slot;
1884         int repl;
1885         struct md_rdev *rdev = NULL;
1886
1887         d = find_bio_disk(conf, r10_bio, bio, &slot, &repl);
1888         if (repl)
1889                 rdev = conf->mirrors[d].replacement;
1890         else
1891                 rdev = conf->mirrors[d].rdev;
1892
1893         if (bio->bi_error) {
1894                 if (repl)
1895                         md_error(mddev, rdev);
1896                 else {
1897                         set_bit(WriteErrorSeen, &rdev->flags);
1898                         if (!test_and_set_bit(WantReplacement, &rdev->flags))
1899                                 set_bit(MD_RECOVERY_NEEDED,
1900                                         &rdev->mddev->recovery);
1901                         set_bit(R10BIO_WriteError, &r10_bio->state);
1902                 }
1903         } else if (is_badblock(rdev,
1904                              r10_bio->devs[slot].addr,
1905                              r10_bio->sectors,
1906                              &first_bad, &bad_sectors))
1907                 set_bit(R10BIO_MadeGood, &r10_bio->state);
1908
1909         rdev_dec_pending(rdev, mddev);
1910
1911         end_sync_request(r10_bio);
1912 }
1913
1914 /*
1915  * Note: sync and recover and handled very differently for raid10
1916  * This code is for resync.
1917  * For resync, we read through virtual addresses and read all blocks.
1918  * If there is any error, we schedule a write.  The lowest numbered
1919  * drive is authoritative.
1920  * However requests come for physical address, so we need to map.
1921  * For every physical address there are raid_disks/copies virtual addresses,
1922  * which is always are least one, but is not necessarly an integer.
1923  * This means that a physical address can span multiple chunks, so we may
1924  * have to submit multiple io requests for a single sync request.
1925  */
1926 /*
1927  * We check if all blocks are in-sync and only write to blocks that
1928  * aren't in sync
1929  */
1930 static void sync_request_write(struct mddev *mddev, struct r10bio *r10_bio)
1931 {
1932         struct r10conf *conf = mddev->private;
1933         int i, first;
1934         struct bio *tbio, *fbio;
1935         int vcnt;
1936
1937         atomic_set(&r10_bio->remaining, 1);
1938
1939         /* find the first device with a block */
1940         for (i=0; i<conf->copies; i++)
1941                 if (!r10_bio->devs[i].bio->bi_error)
1942                         break;
1943
1944         if (i == conf->copies)
1945                 goto done;
1946
1947         first = i;
1948         fbio = r10_bio->devs[i].bio;
1949         fbio->bi_iter.bi_size = r10_bio->sectors << 9;
1950         fbio->bi_iter.bi_idx = 0;
1951
1952         vcnt = (r10_bio->sectors + (PAGE_SIZE >> 9) - 1) >> (PAGE_SHIFT - 9);
1953         /* now find blocks with errors */
1954         for (i=0 ; i < conf->copies ; i++) {
1955                 int  j, d;
1956
1957                 tbio = r10_bio->devs[i].bio;
1958
1959                 if (tbio->bi_end_io != end_sync_read)
1960                         continue;
1961                 if (i == first)
1962                         continue;
1963                 if (!r10_bio->devs[i].bio->bi_error) {
1964                         /* We know that the bi_io_vec layout is the same for
1965                          * both 'first' and 'i', so we just compare them.
1966                          * All vec entries are PAGE_SIZE;
1967                          */
1968                         int sectors = r10_bio->sectors;
1969                         for (j = 0; j < vcnt; j++) {
1970                                 int len = PAGE_SIZE;
1971                                 if (sectors < (len / 512))
1972                                         len = sectors * 512;
1973                                 if (memcmp(page_address(fbio->bi_io_vec[j].bv_page),
1974                                            page_address(tbio->bi_io_vec[j].bv_page),
1975                                            len))
1976                                         break;
1977                                 sectors -= len/512;
1978                         }
1979                         if (j == vcnt)
1980                                 continue;
1981                         atomic64_add(r10_bio->sectors, &mddev->resync_mismatches);
1982                         if (test_bit(MD_RECOVERY_CHECK, &mddev->recovery))
1983                                 /* Don't fix anything. */
1984                                 continue;
1985                 }
1986                 /* Ok, we need to write this bio, either to correct an
1987                  * inconsistency or to correct an unreadable block.
1988                  * First we need to fixup bv_offset, bv_len and
1989                  * bi_vecs, as the read request might have corrupted these
1990                  */
1991                 bio_reset(tbio);
1992
1993                 tbio->bi_vcnt = vcnt;
1994                 tbio->bi_iter.bi_size = fbio->bi_iter.bi_size;
1995                 tbio->bi_rw = WRITE;
1996                 tbio->bi_private = r10_bio;
1997                 tbio->bi_iter.bi_sector = r10_bio->devs[i].addr;
1998                 tbio->bi_end_io = end_sync_write;
1999
2000                 bio_copy_data(tbio, fbio);
2001
2002                 d = r10_bio->devs[i].devnum;
2003                 atomic_inc(&conf->mirrors[d].rdev->nr_pending);
2004                 atomic_inc(&r10_bio->remaining);
2005                 md_sync_acct(conf->mirrors[d].rdev->bdev, bio_sectors(tbio));
2006
2007                 tbio->bi_iter.bi_sector += conf->mirrors[d].rdev->data_offset;
2008                 tbio->bi_bdev = conf->mirrors[d].rdev->bdev;
2009                 generic_make_request(tbio);
2010         }
2011
2012         /* Now write out to any replacement devices
2013          * that are active
2014          */
2015         for (i = 0; i < conf->copies; i++) {
2016                 int d;
2017
2018                 tbio = r10_bio->devs[i].repl_bio;
2019                 if (!tbio || !tbio->bi_end_io)
2020                         continue;
2021                 if (r10_bio->devs[i].bio->bi_end_io != end_sync_write
2022                     && r10_bio->devs[i].bio != fbio)
2023                         bio_copy_data(tbio, fbio);
2024                 d = r10_bio->devs[i].devnum;
2025                 atomic_inc(&r10_bio->remaining);
2026                 md_sync_acct(conf->mirrors[d].replacement->bdev,
2027                              bio_sectors(tbio));
2028                 generic_make_request(tbio);
2029         }
2030
2031 done:
2032         if (atomic_dec_and_test(&r10_bio->remaining)) {
2033                 md_done_sync(mddev, r10_bio->sectors, 1);
2034                 put_buf(r10_bio);
2035         }
2036 }
2037
2038 /*
2039  * Now for the recovery code.
2040  * Recovery happens across physical sectors.
2041  * We recover all non-is_sync drives by finding the virtual address of
2042  * each, and then choose a working drive that also has that virt address.
2043  * There is a separate r10_bio for each non-in_sync drive.
2044  * Only the first two slots are in use. The first for reading,
2045  * The second for writing.
2046  *
2047  */
2048 static void fix_recovery_read_error(struct r10bio *r10_bio)
2049 {
2050         /* We got a read error during recovery.
2051          * We repeat the read in smaller page-sized sections.
2052          * If a read succeeds, write it to the new device or record
2053          * a bad block if we cannot.
2054          * If a read fails, record a bad block on both old and
2055          * new devices.
2056          */
2057         struct mddev *mddev = r10_bio->mddev;
2058         struct r10conf *conf = mddev->private;
2059         struct bio *bio = r10_bio->devs[0].bio;
2060         sector_t sect = 0;
2061         int sectors = r10_bio->sectors;
2062         int idx = 0;
2063         int dr = r10_bio->devs[0].devnum;
2064         int dw = r10_bio->devs[1].devnum;
2065
2066         while (sectors) {
2067                 int s = sectors;
2068                 struct md_rdev *rdev;
2069                 sector_t addr;
2070                 int ok;
2071
2072                 if (s > (PAGE_SIZE>>9))
2073                         s = PAGE_SIZE >> 9;
2074
2075                 rdev = conf->mirrors[dr].rdev;
2076                 addr = r10_bio->devs[0].addr + sect,
2077                 ok = sync_page_io(rdev,
2078                                   addr,
2079                                   s << 9,
2080                                   bio->bi_io_vec[idx].bv_page,
2081                                   READ, false);
2082                 if (ok) {
2083                         rdev = conf->mirrors[dw].rdev;
2084                         addr = r10_bio->devs[1].addr + sect;
2085                         ok = sync_page_io(rdev,
2086                                           addr,
2087                                           s << 9,
2088                                           bio->bi_io_vec[idx].bv_page,
2089                                           WRITE, false);
2090                         if (!ok) {
2091                                 set_bit(WriteErrorSeen, &rdev->flags);
2092                                 if (!test_and_set_bit(WantReplacement,
2093                                                       &rdev->flags))
2094                                         set_bit(MD_RECOVERY_NEEDED,
2095                                                 &rdev->mddev->recovery);
2096                         }
2097                 }
2098                 if (!ok) {
2099                         /* We don't worry if we cannot set a bad block -
2100                          * it really is bad so there is no loss in not
2101                          * recording it yet
2102                          */
2103                         rdev_set_badblocks(rdev, addr, s, 0);
2104
2105                         if (rdev != conf->mirrors[dw].rdev) {
2106                                 /* need bad block on destination too */
2107                                 struct md_rdev *rdev2 = conf->mirrors[dw].rdev;
2108                                 addr = r10_bio->devs[1].addr + sect;
2109                                 ok = rdev_set_badblocks(rdev2, addr, s, 0);
2110                                 if (!ok) {
2111                                         /* just abort the recovery */
2112                                         printk(KERN_NOTICE
2113                                                "md/raid10:%s: recovery aborted"
2114                                                " due to read error\n",
2115                                                mdname(mddev));
2116
2117                                         conf->mirrors[dw].recovery_disabled
2118                                                 = mddev->recovery_disabled;
2119                                         set_bit(MD_RECOVERY_INTR,
2120                                                 &mddev->recovery);
2121                                         break;
2122                                 }
2123                         }
2124                 }
2125
2126                 sectors -= s;
2127                 sect += s;
2128                 idx++;
2129         }
2130 }
2131
2132 static void recovery_request_write(struct mddev *mddev, struct r10bio *r10_bio)
2133 {
2134         struct r10conf *conf = mddev->private;
2135         int d;
2136         struct bio *wbio, *wbio2;
2137
2138         if (!test_bit(R10BIO_Uptodate, &r10_bio->state)) {
2139                 fix_recovery_read_error(r10_bio);
2140                 end_sync_request(r10_bio);
2141                 return;
2142         }
2143
2144         /*
2145          * share the pages with the first bio
2146          * and submit the write request
2147          */
2148         d = r10_bio->devs[1].devnum;
2149         wbio = r10_bio->devs[1].bio;
2150         wbio2 = r10_bio->devs[1].repl_bio;
2151         /* Need to test wbio2->bi_end_io before we call
2152          * generic_make_request as if the former is NULL,
2153          * the latter is free to free wbio2.
2154          */
2155         if (wbio2 && !wbio2->bi_end_io)
2156                 wbio2 = NULL;
2157         if (wbio->bi_end_io) {
2158                 atomic_inc(&conf->mirrors[d].rdev->nr_pending);
2159                 md_sync_acct(conf->mirrors[d].rdev->bdev, bio_sectors(wbio));
2160                 generic_make_request(wbio);
2161         }
2162         if (wbio2) {
2163                 atomic_inc(&conf->mirrors[d].replacement->nr_pending);
2164                 md_sync_acct(conf->mirrors[d].replacement->bdev,
2165                              bio_sectors(wbio2));
2166                 generic_make_request(wbio2);
2167         }
2168 }
2169
2170 /*
2171  * Used by fix_read_error() to decay the per rdev read_errors.
2172  * We halve the read error count for every hour that has elapsed
2173  * since the last recorded read error.
2174  *
2175  */
2176 static void check_decay_read_errors(struct mddev *mddev, struct md_rdev *rdev)
2177 {
2178         struct timespec cur_time_mon;
2179         unsigned long hours_since_last;
2180         unsigned int read_errors = atomic_read(&rdev->read_errors);
2181
2182         ktime_get_ts(&cur_time_mon);
2183
2184         if (rdev->last_read_error.tv_sec == 0 &&
2185             rdev->last_read_error.tv_nsec == 0) {
2186                 /* first time we've seen a read error */
2187                 rdev->last_read_error = cur_time_mon;
2188                 return;
2189         }
2190
2191         hours_since_last = (cur_time_mon.tv_sec -
2192                             rdev->last_read_error.tv_sec) / 3600;
2193
2194         rdev->last_read_error = cur_time_mon;
2195
2196         /*
2197          * if hours_since_last is > the number of bits in read_errors
2198          * just set read errors to 0. We do this to avoid
2199          * overflowing the shift of read_errors by hours_since_last.
2200          */
2201         if (hours_since_last >= 8 * sizeof(read_errors))
2202                 atomic_set(&rdev->read_errors, 0);
2203         else
2204                 atomic_set(&rdev->read_errors, read_errors >> hours_since_last);
2205 }
2206
2207 static int r10_sync_page_io(struct md_rdev *rdev, sector_t sector,
2208                             int sectors, struct page *page, int rw)
2209 {
2210         sector_t first_bad;
2211         int bad_sectors;
2212
2213         if (is_badblock(rdev, sector, sectors, &first_bad, &bad_sectors)
2214             && (rw == READ || test_bit(WriteErrorSeen, &rdev->flags)))
2215                 return -1;
2216         if (sync_page_io(rdev, sector, sectors << 9, page, rw, false))
2217                 /* success */
2218                 return 1;
2219         if (rw == WRITE) {
2220                 set_bit(WriteErrorSeen, &rdev->flags);
2221                 if (!test_and_set_bit(WantReplacement, &rdev->flags))
2222                         set_bit(MD_RECOVERY_NEEDED,
2223                                 &rdev->mddev->recovery);
2224         }
2225         /* need to record an error - either for the block or the device */
2226         if (!rdev_set_badblocks(rdev, sector, sectors, 0))
2227                 md_error(rdev->mddev, rdev);
2228         return 0;
2229 }
2230
2231 /*
2232  * This is a kernel thread which:
2233  *
2234  *      1.      Retries failed read operations on working mirrors.
2235  *      2.      Updates the raid superblock when problems encounter.
2236  *      3.      Performs writes following reads for array synchronising.
2237  */
2238
2239 static void fix_read_error(struct r10conf *conf, struct mddev *mddev, struct r10bio *r10_bio)
2240 {
2241         int sect = 0; /* Offset from r10_bio->sector */
2242         int sectors = r10_bio->sectors;
2243         struct md_rdev*rdev;
2244         int max_read_errors = atomic_read(&mddev->max_corr_read_errors);
2245         int d = r10_bio->devs[r10_bio->read_slot].devnum;
2246
2247         /* still own a reference to this rdev, so it cannot
2248          * have been cleared recently.
2249          */
2250         rdev = conf->mirrors[d].rdev;
2251
2252         if (test_bit(Faulty, &rdev->flags))
2253                 /* drive has already been failed, just ignore any
2254                    more fix_read_error() attempts */
2255                 return;
2256
2257         check_decay_read_errors(mddev, rdev);
2258         atomic_inc(&rdev->read_errors);
2259         if (atomic_read(&rdev->read_errors) > max_read_errors) {
2260                 char b[BDEVNAME_SIZE];
2261                 bdevname(rdev->bdev, b);
2262
2263                 printk(KERN_NOTICE
2264                        "md/raid10:%s: %s: Raid device exceeded "
2265                        "read_error threshold [cur %d:max %d]\n",
2266                        mdname(mddev), b,
2267                        atomic_read(&rdev->read_errors), max_read_errors);
2268                 printk(KERN_NOTICE
2269                        "md/raid10:%s: %s: Failing raid device\n",
2270                        mdname(mddev), b);
2271                 md_error(mddev, conf->mirrors[d].rdev);
2272                 r10_bio->devs[r10_bio->read_slot].bio = IO_BLOCKED;
2273                 return;
2274         }
2275
2276         while(sectors) {
2277                 int s = sectors;
2278                 int sl = r10_bio->read_slot;
2279                 int success = 0;
2280                 int start;
2281
2282                 if (s > (PAGE_SIZE>>9))
2283                         s = PAGE_SIZE >> 9;
2284
2285                 rcu_read_lock();
2286                 do {
2287                         sector_t first_bad;
2288                         int bad_sectors;
2289
2290                         d = r10_bio->devs[sl].devnum;
2291                         rdev = rcu_dereference(conf->mirrors[d].rdev);
2292                         if (rdev &&
2293                             test_bit(In_sync, &rdev->flags) &&
2294                             is_badblock(rdev, r10_bio->devs[sl].addr + sect, s,
2295                                         &first_bad, &bad_sectors) == 0) {
2296                                 atomic_inc(&rdev->nr_pending);
2297                                 rcu_read_unlock();
2298                                 success = sync_page_io(rdev,
2299                                                        r10_bio->devs[sl].addr +
2300                                                        sect,
2301                                                        s<<9,
2302                                                        conf->tmppage, READ, false);
2303                                 rdev_dec_pending(rdev, mddev);
2304                                 rcu_read_lock();
2305                                 if (success)
2306                                         break;
2307                         }
2308                         sl++;
2309                         if (sl == conf->copies)
2310                                 sl = 0;
2311                 } while (!success && sl != r10_bio->read_slot);
2312                 rcu_read_unlock();
2313
2314                 if (!success) {
2315                         /* Cannot read from anywhere, just mark the block
2316                          * as bad on the first device to discourage future
2317                          * reads.
2318                          */
2319                         int dn = r10_bio->devs[r10_bio->read_slot].devnum;
2320                         rdev = conf->mirrors[dn].rdev;
2321
2322                         if (!rdev_set_badblocks(
2323                                     rdev,
2324                                     r10_bio->devs[r10_bio->read_slot].addr
2325                                     + sect,
2326                                     s, 0)) {
2327                                 md_error(mddev, rdev);
2328                                 r10_bio->devs[r10_bio->read_slot].bio
2329                                         = IO_BLOCKED;
2330                         }
2331                         break;
2332                 }
2333
2334                 start = sl;
2335                 /* write it back and re-read */
2336                 rcu_read_lock();
2337                 while (sl != r10_bio->read_slot) {
2338                         char b[BDEVNAME_SIZE];
2339
2340                         if (sl==0)
2341                                 sl = conf->copies;
2342                         sl--;
2343                         d = r10_bio->devs[sl].devnum;
2344                         rdev = rcu_dereference(conf->mirrors[d].rdev);
2345                         if (!rdev ||
2346                             !test_bit(In_sync, &rdev->flags))
2347                                 continue;
2348
2349                         atomic_inc(&rdev->nr_pending);
2350                         rcu_read_unlock();
2351                         if (r10_sync_page_io(rdev,
2352                                              r10_bio->devs[sl].addr +
2353                                              sect,
2354                                              s, conf->tmppage, WRITE)
2355                             == 0) {
2356                                 /* Well, this device is dead */
2357                                 printk(KERN_NOTICE
2358                                        "md/raid10:%s: read correction "
2359                                        "write failed"
2360                                        " (%d sectors at %llu on %s)\n",
2361                                        mdname(mddev), s,
2362                                        (unsigned long long)(
2363                                                sect +
2364                                                choose_data_offset(r10_bio,
2365                                                                   rdev)),
2366                                        bdevname(rdev->bdev, b));
2367                                 printk(KERN_NOTICE "md/raid10:%s: %s: failing "
2368                                        "drive\n",
2369                                        mdname(mddev),
2370                                        bdevname(rdev->bdev, b));
2371                         }
2372                         rdev_dec_pending(rdev, mddev);
2373                         rcu_read_lock();
2374                 }
2375                 sl = start;
2376                 while (sl != r10_bio->read_slot) {
2377                         char b[BDEVNAME_SIZE];
2378
2379                         if (sl==0)
2380                                 sl = conf->copies;
2381                         sl--;
2382                         d = r10_bio->devs[sl].devnum;
2383                         rdev = rcu_dereference(conf->mirrors[d].rdev);
2384                         if (!rdev ||
2385                             !test_bit(In_sync, &rdev->flags))
2386                                 continue;
2387
2388                         atomic_inc(&rdev->nr_pending);
2389                         rcu_read_unlock();
2390                         switch (r10_sync_page_io(rdev,
2391                                              r10_bio->devs[sl].addr +
2392                                              sect,
2393                                              s, conf->tmppage,
2394                                                  READ)) {
2395                         case 0:
2396                                 /* Well, this device is dead */
2397                                 printk(KERN_NOTICE
2398                                        "md/raid10:%s: unable to read back "
2399                                        "corrected sectors"
2400                                        " (%d sectors at %llu on %s)\n",
2401                                        mdname(mddev), s,
2402                                        (unsigned long long)(
2403                                                sect +
2404                                                choose_data_offset(r10_bio, rdev)),
2405                                        bdevname(rdev->bdev, b));
2406                                 printk(KERN_NOTICE "md/raid10:%s: %s: failing "
2407                                        "drive\n",
2408                                        mdname(mddev),
2409                                        bdevname(rdev->bdev, b));
2410                                 break;
2411                         case 1:
2412                                 printk(KERN_INFO
2413                                        "md/raid10:%s: read error corrected"
2414                                        " (%d sectors at %llu on %s)\n",
2415                                        mdname(mddev), s,
2416                                        (unsigned long long)(
2417                                                sect +
2418                                                choose_data_offset(r10_bio, rdev)),
2419                                        bdevname(rdev->bdev, b));
2420                                 atomic_add(s, &rdev->corrected_errors);
2421                         }
2422
2423                         rdev_dec_pending(rdev, mddev);
2424                         rcu_read_lock();
2425                 }
2426                 rcu_read_unlock();
2427
2428                 sectors -= s;
2429                 sect += s;
2430         }
2431 }
2432
2433 static int narrow_write_error(struct r10bio *r10_bio, int i)
2434 {
2435         struct bio *bio = r10_bio->master_bio;
2436         struct mddev *mddev = r10_bio->mddev;
2437         struct r10conf *conf = mddev->private;
2438         struct md_rdev *rdev = conf->mirrors[r10_bio->devs[i].devnum].rdev;
2439         /* bio has the data to be written to slot 'i' where
2440          * we just recently had a write error.
2441          * We repeatedly clone the bio and trim down to one block,
2442          * then try the write.  Where the write fails we record
2443          * a bad block.
2444          * It is conceivable that the bio doesn't exactly align with
2445          * blocks.  We must handle this.
2446          *
2447          * We currently own a reference to the rdev.
2448          */
2449
2450         int block_sectors;
2451         sector_t sector;
2452         int sectors;
2453         int sect_to_write = r10_bio->sectors;
2454         int ok = 1;
2455
2456         if (rdev->badblocks.shift < 0)
2457                 return 0;
2458
2459         block_sectors = roundup(1 << rdev->badblocks.shift,
2460                                 bdev_logical_block_size(rdev->bdev) >> 9);
2461         sector = r10_bio->sector;
2462         sectors = ((r10_bio->sector + block_sectors)
2463                    & ~(sector_t)(block_sectors - 1))
2464                 - sector;
2465
2466         while (sect_to_write) {
2467                 struct bio *wbio;
2468                 if (sectors > sect_to_write)
2469                         sectors = sect_to_write;
2470                 /* Write at 'sector' for 'sectors' */
2471                 wbio = bio_clone_mddev(bio, GFP_NOIO, mddev);
2472                 bio_trim(wbio, sector - bio->bi_iter.bi_sector, sectors);
2473                 wbio->bi_iter.bi_sector = (r10_bio->devs[i].addr+
2474                                    choose_data_offset(r10_bio, rdev) +
2475                                    (sector - r10_bio->sector));
2476                 wbio->bi_bdev = rdev->bdev;
2477                 if (submit_bio_wait(WRITE, wbio) < 0)
2478                         /* Failure! */
2479                         ok = rdev_set_badblocks(rdev, sector,
2480                                                 sectors, 0)
2481                                 && ok;
2482
2483                 bio_put(wbio);
2484                 sect_to_write -= sectors;
2485                 sector += sectors;
2486                 sectors = block_sectors;
2487         }
2488         return ok;
2489 }
2490
2491 static void handle_read_error(struct mddev *mddev, struct r10bio *r10_bio)
2492 {
2493         int slot = r10_bio->read_slot;
2494         struct bio *bio;
2495         struct r10conf *conf = mddev->private;
2496         struct md_rdev *rdev = r10_bio->devs[slot].rdev;
2497         char b[BDEVNAME_SIZE];
2498         unsigned long do_sync;
2499         int max_sectors;
2500
2501         /* we got a read error. Maybe the drive is bad.  Maybe just
2502          * the block and we can fix it.
2503          * We freeze all other IO, and try reading the block from
2504          * other devices.  When we find one, we re-write
2505          * and check it that fixes the read error.
2506          * This is all done synchronously while the array is
2507          * frozen.
2508          */
2509         bio = r10_bio->devs[slot].bio;
2510         bdevname(bio->bi_bdev, b);
2511         bio_put(bio);
2512         r10_bio->devs[slot].bio = NULL;
2513
2514         if (mddev->ro == 0) {
2515                 freeze_array(conf, 1);
2516                 fix_read_error(conf, mddev, r10_bio);
2517                 unfreeze_array(conf);
2518         } else
2519                 r10_bio->devs[slot].bio = IO_BLOCKED;
2520
2521         rdev_dec_pending(rdev, mddev);
2522
2523 read_more:
2524         rdev = read_balance(conf, r10_bio, &max_sectors);
2525         if (rdev == NULL) {
2526                 printk(KERN_ALERT "md/raid10:%s: %s: unrecoverable I/O"
2527                        " read error for block %llu\n",
2528                        mdname(mddev), b,
2529                        (unsigned long long)r10_bio->sector);
2530                 raid_end_bio_io(r10_bio);
2531                 return;
2532         }
2533
2534         do_sync = (r10_bio->master_bio->bi_rw & REQ_SYNC);
2535         slot = r10_bio->read_slot;
2536         printk_ratelimited(
2537                 KERN_ERR
2538                 "md/raid10:%s: %s: redirecting "
2539                 "sector %llu to another mirror\n",
2540                 mdname(mddev),
2541                 bdevname(rdev->bdev, b),
2542                 (unsigned long long)r10_bio->sector);
2543         bio = bio_clone_mddev(r10_bio->master_bio,
2544                               GFP_NOIO, mddev);
2545         bio_trim(bio, r10_bio->sector - bio->bi_iter.bi_sector, max_sectors);
2546         r10_bio->devs[slot].bio = bio;
2547         r10_bio->devs[slot].rdev = rdev;
2548         bio->bi_iter.bi_sector = r10_bio->devs[slot].addr
2549                 + choose_data_offset(r10_bio, rdev);
2550         bio->bi_bdev = rdev->bdev;
2551         bio->bi_rw = READ | do_sync;
2552         bio->bi_private = r10_bio;
2553         bio->bi_end_io = raid10_end_read_request;
2554         if (max_sectors < r10_bio->sectors) {
2555                 /* Drat - have to split this up more */
2556                 struct bio *mbio = r10_bio->master_bio;
2557                 int sectors_handled =
2558                         r10_bio->sector + max_sectors
2559                         - mbio->bi_iter.bi_sector;
2560                 r10_bio->sectors = max_sectors;
2561                 spin_lock_irq(&conf->device_lock);
2562                 if (mbio->bi_phys_segments == 0)
2563                         mbio->bi_phys_segments = 2;
2564                 else
2565                         mbio->bi_phys_segments++;
2566                 spin_unlock_irq(&conf->device_lock);
2567                 generic_make_request(bio);
2568
2569                 r10_bio = mempool_alloc(conf->r10bio_pool,
2570                                         GFP_NOIO);
2571                 r10_bio->master_bio = mbio;
2572                 r10_bio->sectors = bio_sectors(mbio) - sectors_handled;
2573                 r10_bio->state = 0;
2574                 set_bit(R10BIO_ReadError,
2575                         &r10_bio->state);
2576                 r10_bio->mddev = mddev;
2577                 r10_bio->sector = mbio->bi_iter.bi_sector
2578                         + sectors_handled;
2579
2580                 goto read_more;
2581         } else
2582                 generic_make_request(bio);
2583 }
2584
2585 static void handle_write_completed(struct r10conf *conf, struct r10bio *r10_bio)
2586 {
2587         /* Some sort of write request has finished and it
2588          * succeeded in writing where we thought there was a
2589          * bad block.  So forget the bad block.
2590          * Or possibly if failed and we need to record
2591          * a bad block.
2592          */
2593         int m;
2594         struct md_rdev *rdev;
2595
2596         if (test_bit(R10BIO_IsSync, &r10_bio->state) ||
2597             test_bit(R10BIO_IsRecover, &r10_bio->state)) {
2598                 for (m = 0; m < conf->copies; m++) {
2599                         int dev = r10_bio->devs[m].devnum;
2600                         rdev = conf->mirrors[dev].rdev;
2601                         if (r10_bio->devs[m].bio == NULL)
2602                                 continue;
2603                         if (!r10_bio->devs[m].bio->bi_error) {
2604                                 rdev_clear_badblocks(
2605                                         rdev,
2606                                         r10_bio->devs[m].addr,
2607                                         r10_bio->sectors, 0);
2608                         } else {
2609                                 if (!rdev_set_badblocks(
2610                                             rdev,
2611                                             r10_bio->devs[m].addr,
2612                                             r10_bio->sectors, 0))
2613                                         md_error(conf->mddev, rdev);
2614                         }
2615                         rdev = conf->mirrors[dev].replacement;
2616                         if (r10_bio->devs[m].repl_bio == NULL)
2617                                 continue;
2618
2619                         if (!r10_bio->devs[m].repl_bio->bi_error) {
2620                                 rdev_clear_badblocks(
2621                                         rdev,
2622                                         r10_bio->devs[m].addr,
2623                                         r10_bio->sectors, 0);
2624                         } else {
2625                                 if (!rdev_set_badblocks(
2626                                             rdev,
2627                                             r10_bio->devs[m].addr,
2628                                             r10_bio->sectors, 0))
2629                                         md_error(conf->mddev, rdev);
2630                         }
2631                 }
2632                 put_buf(r10_bio);
2633         } else {
2634                 bool fail = false;
2635                 for (m = 0; m < conf->copies; m++) {
2636                         int dev = r10_bio->devs[m].devnum;
2637                         struct bio *bio = r10_bio->devs[m].bio;
2638                         rdev = conf->mirrors[dev].rdev;
2639                         if (bio == IO_MADE_GOOD) {
2640                                 rdev_clear_badblocks(
2641                                         rdev,
2642                                         r10_bio->devs[m].addr,
2643                                         r10_bio->sectors, 0);
2644                                 rdev_dec_pending(rdev, conf->mddev);
2645                         } else if (bio != NULL && bio->bi_error) {
2646                                 fail = true;
2647                                 if (!narrow_write_error(r10_bio, m)) {
2648                                         md_error(conf->mddev, rdev);
2649                                         set_bit(R10BIO_Degraded,
2650                                                 &r10_bio->state);
2651                                 }
2652                                 rdev_dec_pending(rdev, conf->mddev);
2653                         }
2654                         bio = r10_bio->devs[m].repl_bio;
2655                         rdev = conf->mirrors[dev].replacement;
2656                         if (rdev && bio == IO_MADE_GOOD) {
2657                                 rdev_clear_badblocks(
2658                                         rdev,
2659                                         r10_bio->devs[m].addr,
2660                                         r10_bio->sectors, 0);
2661                                 rdev_dec_pending(rdev, conf->mddev);
2662                         }
2663                 }
2664                 if (fail) {
2665                         spin_lock_irq(&conf->device_lock);
2666                         list_add(&r10_bio->retry_list, &conf->bio_end_io_list);
2667                         conf->nr_queued++;
2668                         spin_unlock_irq(&conf->device_lock);
2669                         md_wakeup_thread(conf->mddev->thread);
2670                 } else {
2671                         if (test_bit(R10BIO_WriteError,
2672                                      &r10_bio->state))
2673                                 close_write(r10_bio);
2674                         raid_end_bio_io(r10_bio);
2675                 }
2676         }
2677 }
2678
2679 static void raid10d(struct md_thread *thread)
2680 {
2681         struct mddev *mddev = thread->mddev;
2682         struct r10bio *r10_bio;
2683         unsigned long flags;
2684         struct r10conf *conf = mddev->private;
2685         struct list_head *head = &conf->retry_list;
2686         struct blk_plug plug;
2687
2688         md_check_recovery(mddev);
2689
2690         if (!list_empty_careful(&conf->bio_end_io_list) &&
2691             !test_bit(MD_CHANGE_PENDING, &mddev->flags)) {
2692                 LIST_HEAD(tmp);
2693                 spin_lock_irqsave(&conf->device_lock, flags);
2694                 if (!test_bit(MD_CHANGE_PENDING, &mddev->flags)) {
2695                         while (!list_empty(&conf->bio_end_io_list)) {
2696                                 list_move(conf->bio_end_io_list.prev, &tmp);
2697                                 conf->nr_queued--;
2698                         }
2699                 }
2700                 spin_unlock_irqrestore(&conf->device_lock, flags);
2701                 while (!list_empty(&tmp)) {
2702                         r10_bio = list_first_entry(&tmp, struct r10bio,
2703                                                    retry_list);
2704                         list_del(&r10_bio->retry_list);
2705                         if (mddev->degraded)
2706                                 set_bit(R10BIO_Degraded, &r10_bio->state);
2707
2708                         if (test_bit(R10BIO_WriteError,
2709                                      &r10_bio->state))
2710                                 close_write(r10_bio);
2711                         raid_end_bio_io(r10_bio);
2712                 }
2713         }
2714
2715         blk_start_plug(&plug);
2716         for (;;) {
2717
2718                 flush_pending_writes(conf);
2719
2720                 spin_lock_irqsave(&conf->device_lock, flags);
2721                 if (list_empty(head)) {
2722                         spin_unlock_irqrestore(&conf->device_lock, flags);
2723                         break;
2724                 }
2725                 r10_bio = list_entry(head->prev, struct r10bio, retry_list);
2726                 list_del(head->prev);
2727                 conf->nr_queued--;
2728                 spin_unlock_irqrestore(&conf->device_lock, flags);
2729
2730                 mddev = r10_bio->mddev;
2731                 conf = mddev->private;
2732                 if (test_bit(R10BIO_MadeGood, &r10_bio->state) ||
2733                     test_bit(R10BIO_WriteError, &r10_bio->state))
2734                         handle_write_completed(conf, r10_bio);
2735                 else if (test_bit(R10BIO_IsReshape, &r10_bio->state))
2736                         reshape_request_write(mddev, r10_bio);
2737                 else if (test_bit(R10BIO_IsSync, &r10_bio->state))
2738                         sync_request_write(mddev, r10_bio);
2739                 else if (test_bit(R10BIO_IsRecover, &r10_bio->state))
2740                         recovery_request_write(mddev, r10_bio);
2741                 else if (test_bit(R10BIO_ReadError, &r10_bio->state))
2742                         handle_read_error(mddev, r10_bio);
2743                 else {
2744                         /* just a partial read to be scheduled from a
2745                          * separate context
2746                          */
2747                         int slot = r10_bio->read_slot;
2748                         generic_make_request(r10_bio->devs[slot].bio);
2749                 }
2750
2751                 cond_resched();
2752                 if (mddev->flags & ~(1<<MD_CHANGE_PENDING))
2753                         md_check_recovery(mddev);
2754         }
2755         blk_finish_plug(&plug);
2756 }
2757
2758 static int init_resync(struct r10conf *conf)
2759 {
2760         int buffs;
2761         int i;
2762
2763         buffs = RESYNC_WINDOW / RESYNC_BLOCK_SIZE;
2764         BUG_ON(conf->r10buf_pool);
2765         conf->have_replacement = 0;
2766         for (i = 0; i < conf->geo.raid_disks; i++)
2767                 if (conf->mirrors[i].replacement)
2768                         conf->have_replacement = 1;
2769         conf->r10buf_pool = mempool_create(buffs, r10buf_pool_alloc, r10buf_pool_free, conf);
2770         if (!conf->r10buf_pool)
2771                 return -ENOMEM;
2772         conf->next_resync = 0;
2773         return 0;
2774 }
2775
2776 /*
2777  * perform a "sync" on one "block"
2778  *
2779  * We need to make sure that no normal I/O request - particularly write
2780  * requests - conflict with active sync requests.
2781  *
2782  * This is achieved by tracking pending requests and a 'barrier' concept
2783  * that can be installed to exclude normal IO requests.
2784  *
2785  * Resync and recovery are handled very differently.
2786  * We differentiate by looking at MD_RECOVERY_SYNC in mddev->recovery.
2787  *
2788  * For resync, we iterate over virtual addresses, read all copies,
2789  * and update if there are differences.  If only one copy is live,
2790  * skip it.
2791  * For recovery, we iterate over physical addresses, read a good
2792  * value for each non-in_sync drive, and over-write.
2793  *
2794  * So, for recovery we may have several outstanding complex requests for a
2795  * given address, one for each out-of-sync device.  We model this by allocating
2796  * a number of r10_bio structures, one for each out-of-sync device.
2797  * As we setup these structures, we collect all bio's together into a list
2798  * which we then process collectively to add pages, and then process again
2799  * to pass to generic_make_request.
2800  *
2801  * The r10_bio structures are linked using a borrowed master_bio pointer.
2802  * This link is counted in ->remaining.  When the r10_bio that points to NULL
2803  * has its remaining count decremented to 0, the whole complex operation
2804  * is complete.
2805  *
2806  */
2807
2808 static sector_t raid10_sync_request(struct mddev *mddev, sector_t sector_nr,
2809                              int *skipped)
2810 {
2811         struct r10conf *conf = mddev->private;
2812         struct r10bio *r10_bio;
2813         struct bio *biolist = NULL, *bio;
2814         sector_t max_sector, nr_sectors;
2815         int i;
2816         int max_sync;
2817         sector_t sync_blocks;
2818         sector_t sectors_skipped = 0;
2819         int chunks_skipped = 0;
2820         sector_t chunk_mask = conf->geo.chunk_mask;
2821
2822         if (!conf->r10buf_pool)
2823                 if (init_resync(conf))
2824                         return 0;
2825
2826         /*
2827          * Allow skipping a full rebuild for incremental assembly
2828          * of a clean array, like RAID1 does.
2829          */
2830         if (mddev->bitmap == NULL &&
2831             mddev->recovery_cp == MaxSector &&
2832             mddev->reshape_position == MaxSector &&
2833             !test_bit(MD_RECOVERY_SYNC, &mddev->recovery) &&
2834             !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery) &&
2835             !test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery) &&
2836             conf->fullsync == 0) {
2837                 *skipped = 1;
2838                 return mddev->dev_sectors - sector_nr;
2839         }
2840
2841  skipped:
2842         max_sector = mddev->dev_sectors;
2843         if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery) ||
2844             test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery))
2845                 max_sector = mddev->resync_max_sectors;
2846         if (sector_nr >= max_sector) {
2847                 /* If we aborted, we need to abort the
2848                  * sync on the 'current' bitmap chucks (there can
2849                  * be several when recovering multiple devices).
2850                  * as we may have started syncing it but not finished.
2851                  * We can find the current address in
2852                  * mddev->curr_resync, but for recovery,
2853                  * we need to convert that to several
2854                  * virtual addresses.
2855                  */
2856                 if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery)) {
2857                         end_reshape(conf);
2858                         close_sync(conf);
2859                         return 0;
2860                 }
2861
2862                 if (mddev->curr_resync < max_sector) { /* aborted */
2863                         if (test_bit(MD_RECOVERY_SYNC, &mddev->recovery))
2864                                 bitmap_end_sync(mddev->bitmap, mddev->curr_resync,
2865                                                 &sync_blocks, 1);
2866                         else for (i = 0; i < conf->geo.raid_disks; i++) {
2867                                 sector_t sect =
2868                                         raid10_find_virt(conf, mddev->curr_resync, i);
2869                                 bitmap_end_sync(mddev->bitmap, sect,
2870                                                 &sync_blocks, 1);
2871                         }
2872                 } else {
2873                         /* completed sync */
2874                         if ((!mddev->bitmap || conf->fullsync)
2875                             && conf->have_replacement
2876                             && test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) {
2877                                 /* Completed a full sync so the replacements
2878                                  * are now fully recovered.
2879                                  */
2880                                 for (i = 0; i < conf->geo.raid_disks; i++)
2881                                         if (conf->mirrors[i].replacement)
2882                                                 conf->mirrors[i].replacement
2883                                                         ->recovery_offset
2884                                                         = MaxSector;
2885                         }
2886                         conf->fullsync = 0;
2887                 }
2888                 bitmap_close_sync(mddev->bitmap);
2889                 close_sync(conf);
2890                 *skipped = 1;
2891                 return sectors_skipped;
2892         }
2893
2894         if (test_bit(MD_RECOVERY_RESHAPE, &mddev->recovery))
2895                 return reshape_request(mddev, sector_nr, skipped);
2896
2897         if (chunks_skipped >= conf->geo.raid_disks) {
2898                 /* if there has been nothing to do on any drive,
2899                  * then there is nothing to do at all..
2900                  */
2901                 *skipped = 1;
2902                 return (max_sector - sector_nr) + sectors_skipped;
2903         }
2904
2905         if (max_sector > mddev->resync_max)
2906                 max_sector = mddev->resync_max; /* Don't do IO beyond here */
2907
2908         /* make sure whole request will fit in a chunk - if chunks
2909          * are meaningful
2910          */
2911         if (conf->geo.near_copies < conf->geo.raid_disks &&
2912             max_sector > (sector_nr | chunk_mask))
2913                 max_sector = (sector_nr | chunk_mask) + 1;
2914
2915         /* Again, very different code for resync and recovery.
2916          * Both must result in an r10bio with a list of bios that
2917          * have bi_end_io, bi_sector, bi_bdev set,
2918          * and bi_private set to the r10bio.
2919          * For recovery, we may actually create several r10bios
2920          * with 2 bios in each, that correspond to the bios in the main one.
2921          * In this case, the subordinate r10bios link back through a
2922          * borrowed master_bio pointer, and the counter in the master
2923          * includes a ref from each subordinate.
2924          */
2925         /* First, we decide what to do and set ->bi_end_io
2926          * To end_sync_read if we want to read, and
2927          * end_sync_write if we will want to write.
2928          */
2929
2930         max_sync = RESYNC_PAGES << (PAGE_SHIFT-9);
2931         if (!test_bit(MD_RECOVERY_SYNC, &mddev->recovery)) {
2932                 /* recovery... the complicated one */
2933                 int j;
2934                 r10_bio = NULL;
2935
2936                 for (i = 0 ; i < conf->geo.raid_disks; i++) {
2937                         int still_degraded;
2938                         struct r10bio *rb2;
2939                         sector_t sect;
2940                         int must_sync;
2941                         int any_working;
2942                         struct raid10_info *mirror = &conf->mirrors[i];
2943
2944                         if ((mirror->rdev == NULL ||
2945                              test_bit(In_sync, &mirror->rdev->flags))
2946                             &&
2947                             (mirror->replacement == NULL ||
2948                              test_bit(Faulty,
2949                                       &mirror->replacement->flags)))
2950                                 continue;
2951
2952                         still_degraded = 0;
2953                         /* want to reconstruct this device */
2954                         rb2 = r10_bio;
2955                         sect = raid10_find_virt(conf, sector_nr, i);
2956                         if (sect >= mddev->resync_max_sectors) {
2957                                 /* last stripe is not complete - don't
2958                                  * try to recover this sector.
2959                                  */
2960                                 continue;
2961                         }
2962                         /* Unless we are doing a full sync, or a replacement
2963                          * we only need to recover the block if it is set in
2964                          * the bitmap
2965                          */
2966                         must_sync = bitmap_start_sync(mddev->bitmap, sect,
2967                                                       &sync_blocks, 1);
2968                         if (sync_blocks < max_sync)
2969                                 max_sync = sync_blocks;
2970                         if (!must_sync &&
2971                             mirror->replacement == NULL &&
2972                             !conf->fullsync) {
2973                                 /* yep, skip the sync_blocks here, but don't assume
2974                                  * that there will never be anything to do here
2975                                  */
2976                                 chunks_skipped = -1;
2977                                 continue;
2978                         }
2979
2980                         r10_bio = mempool_alloc(conf->r10buf_pool, GFP_NOIO);
2981                         r10_bio->state = 0;
2982                         raise_barrier(conf, rb2 != NULL);
2983                         atomic_set(&r10_bio->remaining, 0);
2984
2985                         r10_bio->master_bio = (struct bio*)rb2;
2986                         if (rb2)
2987                                 atomic_inc(&rb2->remaining);
2988                         r10_bio->mddev = mddev;
2989                         set_bit(R10BIO_IsRecover, &r10_bio->state);
2990                         r10_bio->sector = sect;
2991
2992                         raid10_find_phys(conf, r10_bio);
2993
2994                         /* Need to check if the array will still be
2995                          * degraded
2996                          */
2997                         for (j = 0; j < conf->geo.raid_disks; j++)
2998                                 if (conf->mirrors[j].rdev == NULL ||
2999                                     test_bit(Faulty, &conf->mirrors[j].rdev->flags)) {
3000                                         still_degraded = 1;
3001                                         break;
3002                                 }
3003
3004                         must_sync = bitmap_start_sync(mddev->bitmap, sect,
3005                                                       &sync_blocks, still_degraded);
3006
3007                         any_working = 0;
3008                         for (j=0; j<conf->copies;j++) {
3009                                 int k;
3010                                 int d = r10_bio->devs[j].devnum;
3011                                 sector_t from_addr, to_addr;
3012                                 struct md_rdev *rdev;
3013                                 sector_t sector, first_bad;
3014                                 int bad_sectors;
3015                                 if (!conf->mirrors[d].rdev ||
3016                                     !test_bit(In_sync, &conf->mirrors[d].rdev->flags))
3017                                         continue;
3018                                 /* This is where we read from */
3019                                 any_working = 1;
3020                                 rdev = conf->mirrors[d].rdev;
3021                                 sector = r10_bio->devs[j].addr;
3022
3023                                 if (is_badblock(rdev, sector, max_sync,
3024                                                 &first_bad, &bad_sectors)) {
3025                                         if (first_bad > sector)
3026                                                 max_sync = first_bad - sector;
3027                                         else {
3028                                                 bad_sectors -= (sector
3029                                                                 - first_bad);
3030                                                 if (max_sync > bad_sectors)
3031                                                         max_sync = bad_sectors;
3032                                                 continue;
3033                                         }
3034                                 }
3035                                 bio = r10_bio->devs[0].bio;
3036                                 bio_reset(bio);
3037                                 bio->bi_next = biolist;
3038                                 biolist = bio;
3039                                 bio->bi_private = r10_bio;
3040                                 bio->bi_end_io = end_sync_read;
3041                                 bio->bi_rw = READ;
3042                                 from_addr = r10_bio->devs[j].addr;
3043                                 bio->bi_iter.bi_sector = from_addr +
3044                                         rdev->data_offset;
3045                                 bio->bi_bdev = rdev->bdev;
3046                                 atomic_inc(&rdev->nr_pending);
3047                                 /* and we write to 'i' (if not in_sync) */
3048
3049                                 for (k=0; k<conf->copies; k++)
3050                                         if (r10_bio->devs[k].devnum == i)
3051                                                 break;
3052                                 BUG_ON(k == conf->copies);
3053                                 to_addr = r10_bio->devs[k].addr;
3054                                 r10_bio->devs[0].devnum = d;
3055                                 r10_bio->devs[0].addr = from_addr;
3056                                 r10_bio->devs[1].devnum = i;
3057                                 r10_bio->devs[1].addr = to_addr;
3058
3059                                 rdev = mirror->rdev;
3060                                 if (!test_bit(In_sync, &rdev->flags)) {
3061                                         bio = r10_bio->devs[1].bio;
3062                                         bio_reset(bio);
3063                                         bio->bi_next = biolist;
3064                                         biolist = bio;
3065                                         bio->bi_private = r10_bio;
3066                                         bio->bi_end_io = end_sync_write;
3067                                         bio->bi_rw = WRITE;
3068                                         bio->bi_iter.bi_sector = to_addr
3069                                                 + rdev->data_offset;
3070                                         bio->bi_bdev = rdev->bdev;
3071                                         atomic_inc(&r10_bio->remaining);
3072                                 } else
3073                                         r10_bio->devs[1].bio->bi_end_io = NULL;
3074
3075                                 /* and maybe write to replacement */
3076                                 bio = r10_bio->devs[1].repl_bio;
3077                                 if (bio)
3078                                         bio->bi_end_io = NULL;
3079                                 rdev = mirror->replacement;
3080                                 /* Note: if rdev != NULL, then bio
3081                                  * cannot be NULL as r10buf_pool_alloc will
3082                                  * have allocated it.
3083                                  * So the second test here is pointless.
3084                                  * But it keeps semantic-checkers happy, and
3085                                  * this comment keeps human reviewers
3086                                  * happy.
3087                                  */
3088                                 if (rdev == NULL || bio == NULL ||
3089                                     test_bit(Faulty, &rdev->flags))
3090                                         break;
3091                                 bio_reset(bio);
3092                                 bio->bi_next = biolist;
3093                                 biolist = bio;
3094                                 bio->bi_private = r10_bio;
3095                                 bio->bi_end_io = end_sync_write;
3096                                 bio->bi_rw = WRITE;
3097                                 bio->bi_iter.bi_sector = to_addr +
3098                                         rdev->data_offset;
3099                                 bio->bi_bdev = rdev->bdev;
3100                                 atomic_inc(&r10_bio->remaining);
3101                                 break;
3102                         }
3103                         if (j == conf->copies) {
3104                                 /* Cannot recover, so abort the recovery or
3105                                  * record a bad block */
3106                                 if (any_working) {
3107                                         /* problem is that there are bad blocks
3108                                          * on other device(s)
3109                                          */
3110                                         int k;
3111                                         for (k = 0; k < conf->copies; k++)
3112                                                 if (r10_bio->devs[k].devnum == i)
3113                                                         break;
3114                                         if (!test_bit(In_sync,
3115                                                       &mirror->rdev->flags)
3116                                             && !rdev_set_badblocks(
3117                                                     mirror->rdev,
3118                                                     r10_bio->devs[k].addr,
3119                                                     max_sync, 0))
3120                                                 any_working = 0;
3121                                         if (mirror->replacement &&
3122                                             !rdev_set_badblocks(
3123                                                     mirror->replacement,
3124                                                     r10_bio->devs[k].addr,
3125                                                     max_sync, 0))
3126                                                 any_working = 0;
3127                                 }
3128                                 if (!any_working)  {
3129                                         if (!test_and_set_bit(MD_RECOVERY_INTR,
3130                                                               &mddev->recovery))
3131                                                 printk(KERN_INFO "md/raid10:%s: insufficient "
3132                                                        "working devices for recovery.\n",
3133                                                        mdname(mddev));
3134                                         mirror->recovery_disabled
3135                                                 = mddev->recovery_disabled;
3136                                 }
3137                                 put_buf(r10_bio);
3138                                 if (rb2)
3139                                         atomic_dec(&rb2->remaining);
3140                                 r10_bio = rb2;
3141                                 break;
3142                         }
3143                 }
3144                 if (biolist == NULL) {
3145                         while (r10_bio) {
3146                                 struct r10bio *rb2 = r10_bio;
3147                                 r10_bio = (struct r10bio*) rb2->master_bio;
3148                                 rb2->master_bio = NULL;
3149                                 put_buf(rb2);
3150                         }
3151                         goto giveup;
3152                 }
3153         } else {
3154                 /* resync. Schedule a read for every block at this virt offset */
3155                 int count = 0;
3156
3157                 bitmap_cond_end_sync(mddev->bitmap, sector_nr, 0);
3158
3159                 if (!bitmap_start_sync(mddev->bitmap, sector_nr,
3160                                        &sync_blocks, mddev->degraded) &&
3161                     !conf->fullsync && !test_bit(MD_RECOVERY_REQUESTED,
3162                                                  &mddev->recovery)) {
3163                         /* We can skip this block */
3164                         *skipped = 1;
3165                         return sync_blocks + sectors_skipped;
3166                 }
3167                 if (sync_blocks < max_sync)
3168                         max_sync = sync_blocks;
3169                 r10_bio = mempool_alloc(conf->r10buf_pool, GFP_NOIO);
3170                 r10_bio->state = 0;
3171
3172                 r10_bio->mddev = mddev;
3173                 atomic_set(&r10_bio->remaining, 0);
3174                 raise_barrier(conf, 0);
3175                 conf->next_resync = sector_nr;
3176
3177                 r10_bio->master_bio = NULL;
3178                 r10_bio->sector = sector_nr;
3179                 set_bit(R10BIO_IsSync, &r10_bio->state);
3180                 raid10_find_phys(conf, r10_bio);
3181                 r10_bio->sectors = (sector_nr | chunk_mask) - sector_nr + 1;
3182
3183                 for (i = 0; i < conf->copies; i++) {
3184                         int d = r10_bio->devs[i].devnum;
3185                         sector_t first_bad, sector;
3186                         int bad_sectors;
3187
3188                         if (r10_bio->devs[i].repl_bio)
3189                                 r10_bio->devs[i].repl_bio->bi_end_io = NULL;
3190
3191                         bio = r10_bio->devs[i].bio;
3192                         bio_reset(bio);
3193                         bio->bi_error = -EIO;
3194                         if (conf->mirrors[d].rdev == NULL ||
3195                             test_bit(Faulty, &conf->mirrors[d].rdev->flags))
3196                                 continue;
3197                         sector = r10_bio->devs[i].addr;
3198                         if (is_badblock(conf->mirrors[d].rdev,
3199                                         sector, max_sync,
3200                                         &first_bad, &bad_sectors)) {
3201                                 if (first_bad > sector)
3202                                         max_sync = first_bad - sector;
3203                                 else {
3204                                         bad_sectors -= (sector - first_bad);
3205                                         if (max_sync > bad_sectors)
3206                                                 max_sync = bad_sectors;
3207                                         continue;
3208                                 }
3209                         }
3210                         atomic_inc(&conf->mirrors[d].rdev->nr_pending);
3211                         atomic_inc(&r10_bio->remaining);
3212                         bio->bi_next = biolist;
3213                         biolist = bio;
3214                         bio->bi_private = r10_bio;
3215                         bio->bi_end_io = end_sync_read;
3216                         bio->bi_rw = READ;
3217                         bio->bi_iter.bi_sector = sector +
3218                                 conf->mirrors[d].rdev->data_offset;
3219                         bio->bi_bdev = conf->mirrors[d].rdev->bdev;
3220                         count++;
3221
3222                         if (conf->mirrors[d].replacement == NULL ||
3223                             test_bit(Faulty,
3224                                      &conf->mirrors[d].replacement->flags))
3225                                 continue;
3226
3227                         /* Need to set up for writing to the replacement */
3228                         bio = r10_bio->devs[i].repl_bio;
3229                         bio_reset(bio);
3230                         bio->bi_error = -EIO;
3231
3232                         sector = r10_bio->devs[i].addr;
3233                         atomic_inc(&conf->mirrors[d].rdev->nr_pending);
3234                         bio->bi_next = biolist;
3235                         biolist = bio;
3236                         bio->bi_private = r10_bio;
3237                         bio->bi_end_io = end_sync_write;
3238                         bio->bi_rw = WRITE;
3239                         bio->bi_iter.bi_sector = sector +
3240                                 conf->mirrors[d].replacement->data_offset;
3241                         bio->bi_bdev = conf->mirrors[d].replacement->bdev;
3242                         count++;
3243                 }
3244
3245                 if (count < 2) {
3246                         for (i=0; i<conf->copies; i++) {
3247                                 int d = r10_bio->devs[i].devnum;
3248                                 if (r10_bio->devs[i].bio->bi_end_io)
3249                                         rdev_dec_pending(conf->mirrors[d].rdev,
3250                                                          mddev);
3251                                 if (r10_bio->devs[i].repl_bio &&
3252                                     r10_bio->devs[i].repl_bio->bi_end_io)
3253                                         rdev_dec_pending(
3254                                                 conf->mirrors[d].replacement,
3255                                                 mddev);
3256                         }
3257                         put_buf(r10_bio);
3258                         biolist = NULL;
3259                         goto giveup;
3260                 }
3261         }
3262
3263         nr_sectors = 0;
3264         if (sector_nr + max_sync < max_sector)
3265                 max_sector = sector_nr + max_sync;
3266         do {
3267                 struct page *page;
3268                 int len = PAGE_SIZE;
3269                 if (sector_nr + (len>>9) > max_sector)
3270                         len = (max_sector - sector_nr) << 9;
3271                 if (len == 0)
3272                         break;
3273                 for (bio= biolist ; bio ; bio=bio->bi_next) {
3274                         struct bio *bio2;
3275                         page = bio->bi_io_vec[bio->bi_vcnt].bv_page;
3276                         if (bio_add_page(bio, page, len, 0))
3277                                 continue;
3278
3279                         /* stop here */
3280                         bio->bi_io_vec[bio->bi_vcnt].bv_page = page;
3281                         for (bio2 = biolist;
3282                              bio2 && bio2 != bio;
3283                              bio2 = bio2->bi_next) {
3284                                 /* remove last page from this bio */
3285                                 bio2->bi_vcnt--;
3286                                 bio2->bi_iter.bi_size -= len;
3287                                 bio_clear_flag(bio2, BIO_SEG_VALID);
3288                         }
3289                         goto bio_full;
3290                 }
3291                 nr_sectors += len>>9;
3292                 sector_nr += len>>9;
3293         } while (biolist->bi_vcnt < RESYNC_PAGES);
3294  bio_full:
3295         r10_bio->sectors = nr_sectors;
3296
3297         while (biolist) {
3298                 bio = biolist;
3299                 biolist = biolist->bi_next;
3300
3301                 bio->bi_next = NULL;
3302                 r10_bio = bio->bi_private;
3303                 r10_bio->sectors = nr_sectors;
3304
3305                 if (bio->bi_end_io == end_sync_read) {
3306                         md_sync_acct(bio->bi_bdev, nr_sectors);
3307                         bio->bi_error = 0;
3308                         generic_make_request(bio);
3309                 }
3310         }
3311
3312         if (sectors_skipped)
3313                 /* pretend they weren't skipped, it makes
3314                  * no important difference in this case
3315                  */
3316                 md_done_sync(mddev, sectors_skipped, 1);
3317
3318         return sectors_skipped + nr_sectors;
3319  giveup:
3320         /* There is nowhere to write, so all non-sync
3321          * drives must be failed or in resync, all drives
3322          * have a bad block, so try the next chunk...
3323          */
3324         if (sector_nr + max_sync < max_sector)
3325                 max_sector = sector_nr + max_sync;
3326
3327         sectors_skipped += (max_sector - sector_nr);
3328         chunks_skipped ++;
3329         sector_nr = max_sector;
3330         goto skipped;
3331 }
3332
3333 static sector_t
3334 raid10_size(struct mddev *mddev, sector_t sectors, int raid_disks)
3335 {
3336         sector_t size;
3337         struct r10conf *conf = mddev->private;
3338
3339         if (!raid_disks)
3340                 raid_disks = min(conf->geo.raid_disks,
3341                                  conf->prev.raid_disks);
3342         if (!sectors)
3343                 sectors = conf->dev_sectors;
3344
3345         size = sectors >> conf->geo.chunk_shift;
3346         sector_div(size, conf->geo.far_copies);
3347         size = size * raid_disks;
3348         sector_div(size, conf->geo.near_copies);
3349
3350         return size << conf->geo.chunk_shift;
3351 }
3352
3353 static void calc_sectors(struct r10conf *conf, sector_t size)
3354 {
3355         /* Calculate the number of sectors-per-device that will
3356          * actually be used, and set conf->dev_sectors and
3357          * conf->stride
3358          */
3359
3360         size = size >> conf->geo.chunk_shift;
3361         sector_div(size, conf->geo.far_copies);
3362         size = size * conf->geo.raid_disks;
3363         sector_div(size, conf->geo.near_copies);
3364         /* 'size' is now the number of chunks in the array */
3365         /* calculate "used chunks per device" */
3366         size = size * conf->copies;
3367
3368         /* We need to round up when dividing by raid_disks to
3369          * get the stride size.
3370          */
3371         size = DIV_ROUND_UP_SECTOR_T(size, conf->geo.raid_disks);
3372
3373         conf->dev_sectors = size << conf->geo.chunk_shift;
3374
3375         if (conf->geo.far_offset)
3376                 conf->geo.stride = 1 << conf->geo.chunk_shift;
3377         else {
3378                 sector_div(size, conf->geo.far_copies);
3379                 conf->geo.stride = size << conf->geo.chunk_shift;
3380         }
3381 }
3382
3383 enum geo_type {geo_new, geo_old, geo_start};
3384 static int setup_geo(struct geom *geo, struct mddev *mddev, enum geo_type new)
3385 {
3386         int nc, fc, fo;
3387         int layout, chunk, disks;
3388         switch (new) {
3389         case geo_old:
3390                 layout = mddev->layout;
3391                 chunk = mddev->chunk_sectors;
3392                 disks = mddev->raid_disks - mddev->delta_disks;
3393                 break;
3394         case geo_new:
3395                 layout = mddev->new_layout;
3396                 chunk = mddev->new_chunk_sectors;
3397                 disks = mddev->raid_disks;
3398                 break;
3399         default: /* avoid 'may be unused' warnings */
3400         case geo_start: /* new when starting reshape - raid_disks not
3401                          * updated yet. */
3402                 layout = mddev->new_layout;
3403                 chunk = mddev->new_chunk_sectors;
3404                 disks = mddev->raid_disks + mddev->delta_disks;
3405                 break;
3406         }
3407         if (layout >> 19)
3408                 return -1;
3409         if (chunk < (PAGE_SIZE >> 9) ||
3410             !is_power_of_2(chunk))
3411                 return -2;
3412         nc = layout & 255;
3413         fc = (layout >> 8) & 255;
3414         fo = layout & (1<<16);
3415         geo->raid_disks = disks;
3416         geo->near_copies = nc;
3417         geo->far_copies = fc;
3418         geo->far_offset = fo;
3419         switch (layout >> 17) {
3420         case 0: /* original layout.  simple but not always optimal */
3421                 geo->far_set_size = disks;
3422                 break;
3423         case 1: /* "improved" layout which was buggy.  Hopefully no-one is
3424                  * actually using this, but leave code here just in case.*/
3425                 geo->far_set_size = disks/fc;
3426                 WARN(geo->far_set_size < fc,
3427                      "This RAID10 layout does not provide data safety - please backup and create new array\n");
3428                 break;
3429         case 2: /* "improved" layout fixed to match documentation */
3430                 geo->far_set_size = fc * nc;
3431                 break;
3432         default: /* Not a valid layout */
3433                 return -1;
3434         }
3435         geo->chunk_mask = chunk - 1;
3436         geo->chunk_shift = ffz(~chunk);
3437         return nc*fc;
3438 }
3439
3440 static struct r10conf *setup_conf(struct mddev *mddev)
3441 {
3442         struct r10conf *conf = NULL;
3443         int err = -EINVAL;
3444         struct geom geo;
3445         int copies;
3446
3447         copies = setup_geo(&geo, mddev, geo_new);
3448
3449         if (copies == -2) {
3450                 printk(KERN_ERR "md/raid10:%s: chunk size must be "
3451                        "at least PAGE_SIZE(%ld) and be a power of 2.\n",
3452                        mdname(mddev), PAGE_SIZE);
3453                 goto out;
3454         }
3455
3456         if (copies < 2 || copies > mddev->raid_disks) {
3457                 printk(KERN_ERR "md/raid10:%s: unsupported raid10 layout: 0x%8x\n",
3458                        mdname(mddev), mddev->new_layout);
3459                 goto out;
3460         }
3461
3462         err = -ENOMEM;
3463         conf = kzalloc(sizeof(struct r10conf), GFP_KERNEL);
3464         if (!conf)
3465                 goto out;
3466
3467         /* FIXME calc properly */
3468         conf->mirrors = kzalloc(sizeof(struct raid10_info)*(mddev->raid_disks +
3469                                                             max(0,-mddev->delta_disks)),
3470                                 GFP_KERNEL);
3471         if (!conf->mirrors)
3472                 goto out;
3473
3474         conf->tmppage = alloc_page(GFP_KERNEL);
3475         if (!conf->tmppage)
3476                 goto out;
3477
3478         conf->geo = geo;
3479         conf->copies = copies;
3480         conf->r10bio_pool = mempool_create(NR_RAID10_BIOS, r10bio_pool_alloc,
3481                                            r10bio_pool_free, conf);
3482         if (!conf->r10bio_pool)
3483                 goto out;
3484
3485         calc_sectors(conf, mddev->dev_sectors);
3486         if (mddev->reshape_position == MaxSector) {
3487                 conf->prev = conf->geo;
3488                 conf->reshape_progress = MaxSector;
3489         } else {
3490                 if (setup_geo(&conf->prev, mddev, geo_old) != conf->copies) {
3491                         err = -EINVAL;
3492                         goto out;
3493                 }
3494                 conf->reshape_progress = mddev->reshape_position;
3495                 if (conf->prev.far_offset)
3496                         conf->prev.stride = 1 << conf->prev.chunk_shift;
3497                 else
3498                         /* far_copies must be 1 */
3499                         conf->prev.stride = conf->dev_sectors;
3500         }
3501         conf->reshape_safe = conf->reshape_progress;
3502         spin_lock_init(&conf->device_lock);
3503         INIT_LIST_HEAD(&conf->retry_list);
3504         INIT_LIST_HEAD(&conf->bio_end_io_list);
3505
3506         spin_lock_init(&conf->resync_lock);
3507         init_waitqueue_head(&conf->wait_barrier);
3508
3509         conf->thread = md_register_thread(raid10d, mddev, "raid10");
3510         if (!conf->thread)
3511                 goto out;
3512
3513         conf->mddev = mddev;
3514         return conf;
3515
3516  out:
3517         if (err == -ENOMEM)
3518                 printk(KERN_ERR "md/raid10:%s: couldn't allocate memory.\n",
3519                        mdname(mddev));
3520         if (conf) {
3521                 mempool_destroy(conf->r10bio_pool);
3522                 kfree(conf->mirrors);
3523                 safe_put_page(conf->tmppage);
3524                 kfree(conf);
3525         }
3526         return ERR_PTR(err);
3527 }
3528
3529 static int raid10_run(struct mddev *mddev)
3530 {
3531         struct r10conf *conf;
3532         int i, disk_idx, chunk_size;
3533         struct raid10_info *disk;
3534         struct md_rdev *rdev;
3535         sector_t size;
3536         sector_t min_offset_diff = 0;
3537         int first = 1;
3538         bool discard_supported = false;
3539
3540         if (mddev->private == NULL) {
3541                 conf = setup_conf(mddev);
3542                 if (IS_ERR(conf))
3543                         return PTR_ERR(conf);
3544                 mddev->private = conf;
3545         }
3546         conf = mddev->private;
3547         if (!conf)
3548                 goto out;
3549
3550         mddev->thread = conf->thread;
3551         conf->thread = NULL;
3552
3553         chunk_size = mddev->chunk_sectors << 9;
3554         if (mddev->queue) {
3555                 blk_queue_max_discard_sectors(mddev->queue,
3556                                               mddev->chunk_sectors);
3557                 blk_queue_max_write_same_sectors(mddev->queue, 0);
3558                 blk_queue_io_min(mddev->queue, chunk_size);
3559                 if (conf->geo.raid_disks % conf->geo.near_copies)
3560                         blk_queue_io_opt(mddev->queue, chunk_size * conf->geo.raid_disks);
3561                 else
3562                         blk_queue_io_opt(mddev->queue, chunk_size *
3563                                          (conf->geo.raid_disks / conf->geo.near_copies));
3564         }
3565
3566         rdev_for_each(rdev, mddev) {
3567                 long long diff;
3568                 struct request_queue *q;
3569
3570                 disk_idx = rdev->raid_disk;
3571                 if (disk_idx < 0)
3572                         continue;
3573                 if (disk_idx >= conf->geo.raid_disks &&
3574                     disk_idx >= conf->prev.raid_disks)
3575                         continue;
3576                 disk = conf->mirrors + disk_idx;
3577
3578                 if (test_bit(Replacement, &rdev->flags)) {
3579                         if (disk->replacement)
3580                                 goto out_free_conf;
3581                         disk->replacement = rdev;
3582                 } else {
3583                         if (disk->rdev)
3584                                 goto out_free_conf;
3585                         disk->rdev = rdev;
3586                 }
3587                 q = bdev_get_queue(rdev->bdev);
3588                 diff = (rdev->new_data_offset - rdev->data_offset);
3589                 if (!mddev->reshape_backwards)
3590                         diff = -diff;
3591                 if (diff < 0)
3592                         diff = 0;
3593                 if (first || diff < min_offset_diff)
3594                         min_offset_diff = diff;
3595
3596                 if (mddev->gendisk)
3597                         disk_stack_limits(mddev->gendisk, rdev->bdev,
3598                                           rdev->data_offset << 9);
3599
3600                 disk->head_position = 0;
3601
3602                 if (blk_queue_discard(bdev_get_queue(rdev->bdev)))
3603                         discard_supported = true;
3604         }
3605
3606         if (mddev->queue) {
3607                 if (discard_supported)
3608                         queue_flag_set_unlocked(QUEUE_FLAG_DISCARD,
3609                                                 mddev->queue);
3610                 else
3611                         queue_flag_clear_unlocked(QUEUE_FLAG_DISCARD,
3612                                                   mddev->queue);
3613         }
3614         /* need to check that every block has at least one working mirror */
3615         if (!enough(conf, -1)) {
3616                 printk(KERN_ERR "md/raid10:%s: not enough operational mirrors.\n",
3617                        mdname(mddev));
3618                 goto out_free_conf;
3619         }
3620
3621         if (conf->reshape_progress != MaxSector) {
3622                 /* must ensure that shape change is supported */
3623                 if (conf->geo.far_copies != 1 &&
3624                     conf->geo.far_offset == 0)
3625                         goto out_free_conf;
3626                 if (conf->prev.far_copies != 1 &&
3627                     conf->prev.far_offset == 0)
3628                         goto out_free_conf;
3629         }
3630
3631         mddev->degraded = 0;
3632         for (i = 0;
3633              i < conf->geo.raid_disks
3634                      || i < conf->prev.raid_disks;
3635              i++) {
3636
3637                 disk = conf->mirrors + i;
3638
3639                 if (!disk->rdev && disk->replacement) {
3640                         /* The replacement is all we have - use it */
3641                         disk->rdev = disk->replacement;
3642                         disk->replacement = NULL;
3643                         clear_bit(Replacement, &disk->rdev->flags);
3644                 }
3645
3646                 if (!disk->rdev ||
3647                     !test_bit(In_sync, &disk->rdev->flags)) {
3648                         disk->head_position = 0;
3649                         mddev->degraded++;
3650                         if (disk->rdev &&
3651                             disk->rdev->saved_raid_disk < 0)
3652                                 conf->fullsync = 1;
3653                 }
3654                 disk->recovery_disabled = mddev->recovery_disabled - 1;
3655         }
3656
3657         if (mddev->recovery_cp != MaxSector)
3658                 printk(KERN_NOTICE "md/raid10:%s: not clean"
3659                        " -- starting background reconstruction\n",
3660                        mdname(mddev));
3661         printk(KERN_INFO
3662                 "md/raid10:%s: active with %d out of %d devices\n",
3663                 mdname(mddev), conf->geo.raid_disks - mddev->degraded,
3664                 conf->geo.raid_disks);
3665         /*
3666          * Ok, everything is just fine now
3667          */
3668         mddev->dev_sectors = conf->dev_sectors;
3669         size = raid10_size(mddev, 0, 0);
3670         md_set_array_sectors(mddev, size);
3671         mddev->resync_max_sectors = size;
3672
3673         if (mddev->queue) {
3674                 int stripe = conf->geo.raid_disks *
3675                         ((mddev->chunk_sectors << 9) / PAGE_SIZE);
3676
3677                 /* Calculate max read-ahead size.
3678                  * We need to readahead at least twice a whole stripe....
3679                  * maybe...
3680                  */
3681                 stripe /= conf->geo.near_copies;
3682                 if (mddev->queue->backing_dev_info.ra_pages < 2 * stripe)
3683                         mddev->queue->backing_dev_info.ra_pages = 2 * stripe;
3684         }
3685
3686         if (md_integrity_register(mddev))
3687                 goto out_free_conf;
3688
3689         if (conf->reshape_progress != MaxSector) {
3690                 unsigned long before_length, after_length;
3691
3692                 before_length = ((1 << conf->prev.chunk_shift) *
3693                                  conf->prev.far_copies);
3694                 after_length = ((1 << conf->geo.chunk_shift) *
3695                                 conf->geo.far_copies);
3696
3697                 if (max(before_length, after_length) > min_offset_diff) {
3698                         /* This cannot work */
3699                         printk("md/raid10: offset difference not enough to continue reshape\n");
3700                         goto out_free_conf;
3701                 }
3702                 conf->offset_diff = min_offset_diff;
3703
3704                 clear_bit(MD_RECOVERY_SYNC, &mddev->recovery);
3705                 clear_bit(MD_RECOVERY_CHECK, &mddev->recovery);
3706                 set_bit(MD_RECOVERY_RESHAPE, &mddev->recovery);
3707                 set_bit(MD_RECOVERY_RUNNING, &mddev->recovery);
3708                 mddev->sync_thread = md_register_thread(md_do_sync, mddev,
3709                                                         "reshape");
3710         }
3711
3712         return 0;
3713
3714 out_free_conf:
3715         md_unregister_thread(&mddev->thread);
3716         mempool_destroy(conf->r10bio_pool);
3717         safe_put_page(conf->tmppage);
3718         kfree(conf->mirrors);
3719         kfree(conf);
3720         mddev->private = NULL;
3721 out:
3722         return -EIO;
3723 }
3724
3725 static void raid10_free(struct mddev *mddev, void *priv)
3726 {
3727         struct r10conf *conf = priv;
3728
3729         mempool_destroy(conf->r10bio_pool);
3730         safe_put_page(conf->tmppage);
3731         kfree(conf->mirrors);
3732         kfree(conf->mirrors_old);
3733         kfree(conf->mirrors_new);
3734         kfree(conf);
3735 }
3736
3737 static void raid10_quiesce(struct mddev *mddev, int state)
3738 {
3739         struct r10conf *conf = mddev->private;
3740
3741         switch(state) {
3742         case 1:
3743                 raise_barrier(conf, 0);
3744                 break;
3745         case 0:
3746                 lower_barrier(conf);
3747                 break;
3748         }
3749 }
3750
3751 static int raid10_resize(struct mddev *mddev, sector_t sectors)
3752 {
3753         /* Resize of 'far' arrays is not supported.
3754          * For 'near' and 'offset' arrays we can set the
3755          * number of sectors used to be an appropriate multiple
3756          * of the chunk size.
3757          * For 'offset', this is far_copies*chunksize.
3758          * For 'near' the multiplier is the LCM of
3759          * near_copies and raid_disks.
3760          * So if far_copies > 1 && !far_offset, fail.
3761          * Else find LCM(raid_disks, near_copy)*far_copies and
3762          * multiply by chunk_size.  Then round to this number.
3763          * This is mostly done by raid10_size()
3764          */
3765         struct r10conf *conf = mddev->private;
3766         sector_t oldsize, size;
3767
3768         if (mddev->reshape_position != MaxSector)
3769                 return -EBUSY;
3770
3771         if (conf->geo.far_copies > 1 && !conf->geo.far_offset)
3772                 return -EINVAL;
3773
3774         oldsize = raid10_size(mddev, 0, 0);
3775         size = raid10_size(mddev, sectors, 0);
3776         if (mddev->external_size &&
3777             mddev->array_sectors > size)
3778                 return -EINVAL;
3779         if (mddev->bitmap) {
3780                 int ret = bitmap_resize(mddev->bitmap, size, 0, 0);
3781                 if (ret)
3782                         return ret;
3783         }
3784         md_set_array_sectors(mddev, size);
3785         if (mddev->queue) {
3786                 set_capacity(mddev->gendisk, mddev->array_sectors);
3787                 revalidate_disk(mddev->gendisk);
3788         }
3789         if (sectors > mddev->dev_sectors &&
3790             mddev->recovery_cp > oldsize) {
3791                 mddev->recovery_cp = oldsize;
3792                 set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
3793         }
3794         calc_sectors(conf, sectors);
3795         mddev->dev_sectors = conf->dev_sectors;
3796         mddev->resync_max_sectors = size;
3797         return 0;
3798 }
3799
3800 static void *raid10_takeover_raid0(struct mddev *mddev, sector_t size, int devs)
3801 {
3802         struct md_rdev *rdev;
3803         struct r10conf *conf;
3804
3805         if (mddev->degraded > 0) {
3806                 printk(KERN_ERR "md/raid10:%s: Error: degraded raid0!\n",
3807                        mdname(mddev));
3808                 return ERR_PTR(-EINVAL);
3809         }
3810         sector_div(size, devs);
3811
3812         /* Set new parameters */
3813         mddev->new_level = 10;
3814         /* new layout: far_copies = 1, near_copies = 2 */
3815         mddev->new_layout = (1<<8) + 2;
3816         mddev->new_chunk_sectors = mddev->chunk_sectors;
3817         mddev->delta_disks = mddev->raid_disks;
3818         mddev->raid_disks *= 2;
3819         /* make sure it will be not marked as dirty */
3820         mddev->recovery_cp = MaxSector;
3821         mddev->dev_sectors = size;
3822
3823         conf = setup_conf(mddev);
3824         if (!IS_ERR(conf)) {
3825                 rdev_for_each(rdev, mddev)
3826                         if (rdev->raid_disk >= 0) {
3827                                 rdev->new_raid_disk = rdev->raid_disk * 2;
3828                                 rdev->sectors = size;
3829                         }
3830                 conf->barrier = 1;
3831         }
3832
3833         return conf;
3834 }
3835
3836 static void *raid10_takeover(struct mddev *mddev)
3837 {
3838         struct r0conf *raid0_conf;
3839
3840         /* raid10 can take over:
3841          *  raid0 - providing it has only two drives
3842          */
3843         if (mddev->level == 0) {
3844                 /* for raid0 takeover only one zone is supported */
3845                 raid0_conf = mddev->private;
3846                 if (raid0_conf->nr_strip_zones > 1) {
3847                         printk(KERN_ERR "md/raid10:%s: cannot takeover raid 0"
3848                                " with more than one zone.\n",
3849                                mdname(mddev));
3850                         return ERR_PTR(-EINVAL);
3851                 }
3852                 return raid10_takeover_raid0(mddev,
3853                         raid0_conf->strip_zone->zone_end,
3854                         raid0_conf->strip_zone->nb_dev);
3855         }
3856         return ERR_PTR(-EINVAL);
3857 }
3858
3859 static int raid10_check_reshape(struct mddev *mddev)
3860 {
3861         /* Called when there is a request to change
3862          * - layout (to ->new_layout)
3863          * - chunk size (to ->new_chunk_sectors)
3864          * - raid_disks (by delta_disks)
3865          * or when trying to restart a reshape that was ongoing.
3866          *
3867          * We need to validate the request and possibly allocate
3868          * space if that might be an issue later.
3869          *
3870          * Currently we reject any reshape of a 'far' mode array,
3871          * allow chunk size to change if new is generally acceptable,
3872          * allow raid_disks to increase, and allow
3873          * a switch between 'near' mode and 'offset' mode.
3874          */
3875         struct r10conf *conf = mddev->private;
3876         struct geom geo;
3877
3878         if (conf->geo.far_copies != 1 && !conf->geo.far_offset)
3879                 return -EINVAL;
3880
3881         if (setup_geo(&geo, mddev, geo_start) != conf->copies)
3882                 /* mustn't change number of copies */
3883                 return -EINVAL;
3884         if (geo.far_copies > 1 && !geo.far_offset)
3885                 /* Cannot switch to 'far' mode */
3886                 return -EINVAL;
3887
3888         if (mddev->array_sectors & geo.chunk_mask)
3889                         /* not factor of array size */
3890                         return -EINVAL;
3891
3892         if (!enough(conf, -1))
3893                 return -EINVAL;
3894
3895         kfree(conf->mirrors_new);
3896         conf->mirrors_new = NULL;
3897         if (mddev->delta_disks > 0) {
3898                 /* allocate new 'mirrors' list */
3899                 conf->mirrors_new = kzalloc(
3900                         sizeof(struct raid10_info)
3901                         *(mddev->raid_disks +
3902                           mddev->delta_disks),
3903                         GFP_KERNEL);
3904                 if (!conf->mirrors_new)
3905                         return -ENOMEM;
3906         }
3907         return 0;
3908 }
3909
3910 /*
3911  * Need to check if array has failed when deciding whether to:
3912  *  - start an array
3913  *  - remove non-faulty devices
3914  *  - add a spare
3915  *  - allow a reshape
3916  * This determination is simple when no reshape is happening.
3917  * However if there is a reshape, we need to carefully check
3918  * both the before and after sections.
3919  * This is because some failed devices may only affect one
3920  * of the two sections, and some non-in_sync devices may
3921  * be insync in the section most affected by failed devices.
3922  */
3923 static int calc_degraded(struct r10conf *conf)
3924 {
3925         int degraded, degraded2;
3926         int i;
3927
3928         rcu_read_lock();
3929         degraded = 0;
3930         /* 'prev' section first */
3931         for (i = 0; i < conf->prev.raid_disks; i++) {
3932                 struct md_rdev *rdev = rcu_dereference(conf->mirrors[i].rdev);
3933                 if (!rdev || test_bit(Faulty, &rdev->flags))
3934                         degraded++;
3935                 else if (!test_bit(In_sync, &rdev->flags))
3936                         /* When we can reduce the number of devices in
3937                          * an array, this might not contribute to
3938                          * 'degraded'.  It does now.
3939                          */
3940                         degraded++;
3941         }
3942         rcu_read_unlock();
3943         if (conf->geo.raid_disks == conf->prev.raid_disks)
3944                 return degraded;
3945         rcu_read_lock();
3946         degraded2 = 0;
3947         for (i = 0; i < conf->geo.raid_disks; i++) {
3948                 struct md_rdev *rdev = rcu_dereference(conf->mirrors[i].rdev);
3949                 if (!rdev || test_bit(Faulty, &rdev->flags))
3950                         degraded2++;
3951                 else if (!test_bit(In_sync, &rdev->flags)) {
3952                         /* If reshape is increasing the number of devices,
3953                          * this section has already been recovered, so
3954                          * it doesn't contribute to degraded.
3955                          * else it does.
3956                          */
3957                         if (conf->geo.raid_disks <= conf->prev.raid_disks)
3958                                 degraded2++;
3959                 }
3960         }
3961         rcu_read_unlock();
3962         if (degraded2 > degraded)
3963                 return degraded2;
3964         return degraded;
3965 }
3966
3967 static int raid10_start_reshape(struct mddev *mddev)
3968 {
3969         /* A 'reshape' has been requested. This commits
3970          * the various 'new' fields and sets MD_RECOVER_RESHAPE
3971          * This also checks if there are enough spares and adds them
3972          * to the array.
3973          * We currently require enough spares to make the final
3974          * array non-degraded.  We also require that the difference
3975          * between old and new data_offset - on each device - is
3976          * enough that we never risk over-writing.
3977          */
3978
3979         unsigned long before_length, after_length;
3980         sector_t min_offset_diff = 0;
3981         int first = 1;
3982         struct geom new;
3983         struct r10conf *conf = mddev->private;
3984         struct md_rdev *rdev;
3985         int spares = 0;
3986         int ret;
3987
3988         if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery))
3989                 return -EBUSY;
3990
3991         if (setup_geo(&new, mddev, geo_start) != conf->copies)
3992                 return -EINVAL;
3993
3994         before_length = ((1 << conf->prev.chunk_shift) *
3995                          conf->prev.far_copies);
3996         after_length = ((1 << conf->geo.chunk_shift) *
3997                         conf->geo.far_copies);
3998
3999         rdev_for_each(rdev, mddev) {
4000                 if (!test_bit(In_sync, &rdev->flags)
4001                     && !test_bit(Faulty, &rdev->flags))
4002                         spares++;
4003                 if (rdev->raid_disk >= 0) {
4004                         long long diff = (rdev->new_data_offset
4005                                           - rdev->data_offset);
4006                         if (!mddev->reshape_backwards)
4007                                 diff = -diff;
4008                         if (diff < 0)
4009                                 diff = 0;
4010                         if (first || diff < min_offset_diff)
4011                                 min_offset_diff = diff;
4012                 }
4013         }
4014
4015         if (max(before_length, after_length) > min_offset_diff)
4016                 return -EINVAL;
4017
4018         if (spares < mddev->delta_disks)
4019                 return -EINVAL;
4020
4021         conf->offset_diff = min_offset_diff;
4022         spin_lock_irq(&conf->device_lock);
4023         if (conf->mirrors_new) {
4024                 memcpy(conf->mirrors_new, conf->mirrors,
4025                        sizeof(struct raid10_info)*conf->prev.raid_disks);
4026                 smp_mb();
4027                 kfree(conf->mirrors_old);
4028                 conf->mirrors_old = conf->mirrors;
4029                 conf->mirrors = conf->mirrors_new;
4030                 conf->mirrors_new = NULL;
4031         }
4032         setup_geo(&conf->geo, mddev, geo_start);
4033         smp_mb();
4034         if (mddev->reshape_backwards) {
4035                 sector_t size = raid10_size(mddev, 0, 0);
4036                 if (size < mddev->array_sectors) {
4037                         spin_unlock_irq(&conf->device_lock);
4038                         printk(KERN_ERR "md/raid10:%s: array size must be reduce before number of disks\n",
4039                                mdname(mddev));
4040                         return -EINVAL;
4041                 }
4042                 mddev->resync_max_sectors = size;
4043                 conf->reshape_progress = size;
4044         } else
4045                 conf->reshape_progress = 0;
4046         conf->reshape_safe = conf->reshape_progress;
4047         spin_unlock_irq(&conf->device_lock);
4048
4049         if (mddev->delta_disks && mddev->bitmap) {
4050                 ret = bitmap_resize(mddev->bitmap,
4051                                     raid10_size(mddev, 0,
4052                                                 conf->geo.raid_disks),
4053                                     0, 0);
4054                 if (ret)
4055                         goto abort;
4056         }
4057         if (mddev->delta_disks > 0) {
4058                 rdev_for_each(rdev, mddev)
4059                         if (rdev->raid_disk < 0 &&
4060                             !test_bit(Faulty, &rdev->flags)) {
4061                                 if (raid10_add_disk(mddev, rdev) == 0) {
4062                                         if (rdev->raid_disk >=
4063                                             conf->prev.raid_disks)
4064                                                 set_bit(In_sync, &rdev->flags);
4065                                         else
4066                                                 rdev->recovery_offset = 0;
4067
4068                                         if (sysfs_link_rdev(mddev, rdev))
4069                                                 /* Failure here  is OK */;
4070                                 }
4071                         } else if (rdev->raid_disk >= conf->prev.raid_disks
4072                                    && !test_bit(Faulty, &rdev->flags)) {
4073                                 /* This is a spare that was manually added */
4074                                 set_bit(In_sync, &rdev->flags);
4075                         }
4076         }
4077         /* When a reshape changes the number of devices,
4078          * ->degraded is measured against the larger of the
4079          * pre and  post numbers.
4080          */
4081         spin_lock_irq(&conf->device_lock);
4082         mddev->degraded = calc_degraded(conf);
4083         spin_unlock_irq(&conf->device_lock);
4084         mddev->raid_disks = conf->geo.raid_disks;
4085         mddev->reshape_position = conf->reshape_progress;
4086         set_bit(MD_CHANGE_DEVS, &mddev->flags);
4087
4088         clear_bit(MD_RECOVERY_SYNC, &mddev->recovery);
4089         clear_bit(MD_RECOVERY_CHECK, &mddev->recovery);
4090         clear_bit(MD_RECOVERY_DONE, &mddev->recovery);
4091         set_bit(MD_RECOVERY_RESHAPE, &mddev->recovery);
4092         set_bit(MD_RECOVERY_RUNNING, &mddev->recovery);
4093
4094         mddev->sync_thread = md_register_thread(md_do_sync, mddev,
4095                                                 "reshape");
4096         if (!mddev->sync_thread) {
4097                 ret = -EAGAIN;
4098                 goto abort;
4099         }
4100         conf->reshape_checkpoint = jiffies;
4101         md_wakeup_thread(mddev->sync_thread);
4102         md_new_event(mddev);
4103         return 0;
4104
4105 abort:
4106         mddev->recovery = 0;
4107         spin_lock_irq(&conf->device_lock);
4108         conf->geo = conf->prev;
4109         mddev->raid_disks = conf->geo.raid_disks;
4110         rdev_for_each(rdev, mddev)
4111                 rdev->new_data_offset = rdev->data_offset;
4112         smp_wmb();
4113         conf->reshape_progress = MaxSector;
4114         conf->reshape_safe = MaxSector;
4115         mddev->reshape_position = MaxSector;
4116         spin_unlock_irq(&conf->device_lock);
4117         return ret;
4118 }
4119
4120 /* Calculate the last device-address that could contain
4121  * any block from the chunk that includes the array-address 's'
4122  * and report the next address.
4123  * i.e. the address returned will be chunk-aligned and after
4124  * any data that is in the chunk containing 's'.
4125  */
4126 static sector_t last_dev_address(sector_t s, struct geom *geo)
4127 {
4128         s = (s | geo->chunk_mask) + 1;
4129         s >>= geo->chunk_shift;
4130         s *= geo->near_copies;
4131         s = DIV_ROUND_UP_SECTOR_T(s, geo->raid_disks);
4132         s *= geo->far_copies;
4133         s <<= geo->chunk_shift;
4134         return s;
4135 }
4136
4137 /* Calculate the first device-address that could contain
4138  * any block from the chunk that includes the array-address 's'.
4139  * This too will be the start of a chunk
4140  */
4141 static sector_t first_dev_address(sector_t s, struct geom *geo)
4142 {
4143         s >>= geo->chunk_shift;
4144         s *= geo->near_copies;
4145         sector_div(s, geo->raid_disks);
4146         s *= geo->far_copies;
4147         s <<= geo->chunk_shift;
4148         return s;
4149 }
4150
4151 static sector_t reshape_request(struct mddev *mddev, sector_t sector_nr,
4152                                 int *skipped)
4153 {
4154         /* We simply copy at most one chunk (smallest of old and new)
4155          * at a time, possibly less if that exceeds RESYNC_PAGES,
4156          * or we hit a bad block or something.
4157          * This might mean we pause for normal IO in the middle of
4158          * a chunk, but that is not a problem as mddev->reshape_position
4159          * can record any location.
4160          *
4161          * If we will want to write to a location that isn't
4162          * yet recorded as 'safe' (i.e. in metadata on disk) then
4163          * we need to flush all reshape requests and update the metadata.
4164          *
4165          * When reshaping forwards (e.g. to more devices), we interpret
4166          * 'safe' as the earliest block which might not have been copied
4167          * down yet.  We divide this by previous stripe size and multiply
4168          * by previous stripe length to get lowest device offset that we
4169          * cannot write to yet.
4170          * We interpret 'sector_nr' as an address that we want to write to.
4171          * From this we use last_device_address() to find where we might
4172          * write to, and first_device_address on the  'safe' position.
4173          * If this 'next' write position is after the 'safe' position,
4174          * we must update the metadata to increase the 'safe' position.
4175          *
4176          * When reshaping backwards, we round in the opposite direction
4177          * and perform the reverse test:  next write position must not be
4178          * less than current safe position.
4179          *
4180          * In all this the minimum difference in data offsets
4181          * (conf->offset_diff - always positive) allows a bit of slack,
4182          * so next can be after 'safe', but not by more than offset_diff
4183          *
4184          * We need to prepare all the bios here before we start any IO
4185          * to ensure the size we choose is acceptable to all devices.
4186          * The means one for each copy for write-out and an extra one for
4187          * read-in.
4188          * We store the read-in bio in ->master_bio and the others in
4189          * ->devs[x].bio and ->devs[x].repl_bio.
4190          */
4191         struct r10conf *conf = mddev->private;
4192         struct r10bio *r10_bio;
4193         sector_t next, safe, last;
4194         int max_sectors;
4195         int nr_sectors;
4196         int s;
4197         struct md_rdev *rdev;
4198         int need_flush = 0;
4199         struct bio *blist;
4200         struct bio *bio, *read_bio;
4201         int sectors_done = 0;
4202
4203         if (sector_nr == 0) {
4204                 /* If restarting in the middle, skip the initial sectors */
4205                 if (mddev->reshape_backwards &&
4206                     conf->reshape_progress < raid10_size(mddev, 0, 0)) {
4207                         sector_nr = (raid10_size(mddev, 0, 0)
4208                                      - conf->reshape_progress);
4209                 } else if (!mddev->reshape_backwards &&
4210                            conf->reshape_progress > 0)
4211                         sector_nr = conf->reshape_progress;
4212                 if (sector_nr) {
4213                         mddev->curr_resync_completed = sector_nr;
4214                         sysfs_notify(&mddev->kobj, NULL, "sync_completed");
4215                         *skipped = 1;
4216                         return sector_nr;
4217                 }
4218         }
4219
4220         /* We don't use sector_nr to track where we are up to
4221          * as that doesn't work well for ->reshape_backwards.
4222          * So just use ->reshape_progress.
4223          */
4224         if (mddev->reshape_backwards) {
4225                 /* 'next' is the earliest device address that we might
4226                  * write to for this chunk in the new layout
4227                  */
4228                 next = first_dev_address(conf->reshape_progress - 1,
4229                                          &conf->geo);
4230
4231                 /* 'safe' is the last device address that we might read from
4232                  * in the old layout after a restart
4233                  */
4234                 safe = last_dev_address(conf->reshape_safe - 1,
4235                                         &conf->prev);
4236
4237                 if (next + conf->offset_diff < safe)
4238                         need_flush = 1;
4239
4240                 last = conf->reshape_progress - 1;
4241                 sector_nr = last & ~(sector_t)(conf->geo.chunk_mask
4242                                                & conf->prev.chunk_mask);
4243                 if (sector_nr + RESYNC_BLOCK_SIZE/512 < last)
4244                         sector_nr = last + 1 - RESYNC_BLOCK_SIZE/512;
4245         } else {
4246                 /* 'next' is after the last device address that we
4247                  * might write to for this chunk in the new layout
4248                  */
4249                 next = last_dev_address(conf->reshape_progress, &conf->geo);
4250
4251                 /* 'safe' is the earliest device address that we might
4252                  * read from in the old layout after a restart
4253                  */
4254                 safe = first_dev_address(conf->reshape_safe, &conf->prev);
4255
4256                 /* Need to update metadata if 'next' might be beyond 'safe'
4257                  * as that would possibly corrupt data
4258                  */
4259                 if (next > safe + conf->offset_diff)
4260                         need_flush = 1;
4261
4262                 sector_nr = conf->reshape_progress;
4263                 last  = sector_nr | (conf->geo.chunk_mask
4264                                      & conf->prev.chunk_mask);
4265
4266                 if (sector_nr + RESYNC_BLOCK_SIZE/512 <= last)
4267                         last = sector_nr + RESYNC_BLOCK_SIZE/512 - 1;
4268         }
4269
4270         if (need_flush ||
4271             time_after(jiffies, conf->reshape_checkpoint + 10*HZ)) {
4272                 /* Need to update reshape_position in metadata */
4273                 wait_barrier(conf);
4274                 mddev->reshape_position = conf->reshape_progress;
4275                 if (mddev->reshape_backwards)
4276                         mddev->curr_resync_completed = raid10_size(mddev, 0, 0)
4277                                 - conf->reshape_progress;
4278                 else
4279                         mddev->curr_resync_completed = conf->reshape_progress;
4280                 conf->reshape_checkpoint = jiffies;
4281                 set_bit(MD_CHANGE_DEVS, &mddev->flags);
4282                 md_wakeup_thread(mddev->thread);
4283                 wait_event(mddev->sb_wait, mddev->flags == 0 ||
4284                            test_bit(MD_RECOVERY_INTR, &mddev->recovery));
4285                 if (test_bit(MD_RECOVERY_INTR, &mddev->recovery)) {
4286                         allow_barrier(conf);
4287                         return sectors_done;
4288                 }
4289                 conf->reshape_safe = mddev->reshape_position;
4290                 allow_barrier(conf);
4291         }
4292
4293 read_more:
4294         /* Now schedule reads for blocks from sector_nr to last */
4295         r10_bio = mempool_alloc(conf->r10buf_pool, GFP_NOIO);
4296         r10_bio->state = 0;
4297         raise_barrier(conf, sectors_done != 0);
4298         atomic_set(&r10_bio->remaining, 0);
4299         r10_bio->mddev = mddev;
4300         r10_bio->sector = sector_nr;
4301         set_bit(R10BIO_IsReshape, &r10_bio->state);
4302         r10_bio->sectors = last - sector_nr + 1;
4303         rdev = read_balance(conf, r10_bio, &max_sectors);
4304         BUG_ON(!test_bit(R10BIO_Previous, &r10_bio->state));
4305
4306         if (!rdev) {
4307                 /* Cannot read from here, so need to record bad blocks
4308                  * on all the target devices.
4309                  */
4310                 // FIXME
4311                 mempool_free(r10_bio, conf->r10buf_pool);
4312                 set_bit(MD_RECOVERY_INTR, &mddev->recovery);
4313                 return sectors_done;
4314         }
4315
4316         read_bio = bio_alloc_mddev(GFP_KERNEL, RESYNC_PAGES, mddev);
4317
4318         read_bio->bi_bdev = rdev->bdev;
4319         read_bio->bi_iter.bi_sector = (r10_bio->devs[r10_bio->read_slot].addr
4320                                + rdev->data_offset);
4321         read_bio->bi_private = r10_bio;
4322         read_bio->bi_end_io = end_sync_read;
4323         read_bio->bi_rw = READ;
4324         read_bio->bi_flags &= (~0UL << BIO_RESET_BITS);
4325         read_bio->bi_error = 0;
4326         read_bio->bi_vcnt = 0;
4327         read_bio->bi_iter.bi_size = 0;
4328         r10_bio->master_bio = read_bio;
4329         r10_bio->read_slot = r10_bio->devs[r10_bio->read_slot].devnum;
4330
4331         /* Now find the locations in the new layout */
4332         __raid10_find_phys(&conf->geo, r10_bio);
4333
4334         blist = read_bio;
4335         read_bio->bi_next = NULL;
4336
4337         for (s = 0; s < conf->copies*2; s++) {
4338                 struct bio *b;
4339                 int d = r10_bio->devs[s/2].devnum;
4340                 struct md_rdev *rdev2;
4341                 if (s&1) {
4342                         rdev2 = conf->mirrors[d].replacement;
4343                         b = r10_bio->devs[s/2].repl_bio;
4344                 } else {
4345                         rdev2 = conf->mirrors[d].rdev;
4346                         b = r10_bio->devs[s/2].bio;
4347                 }
4348                 if (!rdev2 || test_bit(Faulty, &rdev2->flags))
4349                         continue;
4350
4351                 bio_reset(b);
4352                 b->bi_bdev = rdev2->bdev;
4353                 b->bi_iter.bi_sector = r10_bio->devs[s/2].addr +
4354                         rdev2->new_data_offset;
4355                 b->bi_private = r10_bio;
4356                 b->bi_end_io = end_reshape_write;
4357                 b->bi_rw = WRITE;
4358                 b->bi_next = blist;
4359                 blist = b;
4360         }
4361
4362         /* Now add as many pages as possible to all of these bios. */
4363
4364         nr_sectors = 0;
4365         for (s = 0 ; s < max_sectors; s += PAGE_SIZE >> 9) {
4366                 struct page *page = r10_bio->devs[0].bio->bi_io_vec[s/(PAGE_SIZE>>9)].bv_page;
4367                 int len = (max_sectors - s) << 9;
4368                 if (len > PAGE_SIZE)
4369                         len = PAGE_SIZE;
4370                 for (bio = blist; bio ; bio = bio->bi_next) {
4371                         struct bio *bio2;
4372                         if (bio_add_page(bio, page, len, 0))
4373                                 continue;
4374
4375                         /* Didn't fit, must stop */
4376                         for (bio2 = blist;
4377                              bio2 && bio2 != bio;
4378                              bio2 = bio2->bi_next) {
4379                                 /* Remove last page from this bio */
4380                                 bio2->bi_vcnt--;
4381                                 bio2->bi_iter.bi_size -= len;
4382                                 bio_clear_flag(bio2, BIO_SEG_VALID);
4383                         }
4384                         goto bio_full;
4385                 }
4386                 sector_nr += len >> 9;
4387                 nr_sectors += len >> 9;
4388         }
4389 bio_full:
4390         r10_bio->sectors = nr_sectors;
4391
4392         /* Now submit the read */
4393         md_sync_acct(read_bio->bi_bdev, r10_bio->sectors);
4394         atomic_inc(&r10_bio->remaining);
4395         read_bio->bi_next = NULL;
4396         generic_make_request(read_bio);
4397         sector_nr += nr_sectors;
4398         sectors_done += nr_sectors;
4399         if (sector_nr <= last)
4400                 goto read_more;
4401
4402         /* Now that we have done the whole section we can
4403          * update reshape_progress
4404          */
4405         if (mddev->reshape_backwards)
4406                 conf->reshape_progress -= sectors_done;
4407         else
4408                 conf->reshape_progress += sectors_done;
4409
4410         return sectors_done;
4411 }
4412
4413 static void end_reshape_request(struct r10bio *r10_bio);
4414 static int handle_reshape_read_error(struct mddev *mddev,
4415                                      struct r10bio *r10_bio);
4416 static void reshape_request_write(struct mddev *mddev, struct r10bio *r10_bio)
4417 {
4418         /* Reshape read completed.  Hopefully we have a block
4419          * to write out.
4420          * If we got a read error then we do sync 1-page reads from
4421          * elsewhere until we find the data - or give up.
4422          */
4423         struct r10conf *conf = mddev->private;
4424         int s;
4425
4426         if (!test_bit(R10BIO_Uptodate, &r10_bio->state))
4427                 if (handle_reshape_read_error(mddev, r10_bio) < 0) {
4428                         /* Reshape has been aborted */
4429                         md_done_sync(mddev, r10_bio->sectors, 0);
4430                         return;
4431                 }
4432
4433         /* We definitely have the data in the pages, schedule the
4434          * writes.
4435          */
4436         atomic_set(&r10_bio->remaining, 1);
4437         for (s = 0; s < conf->copies*2; s++) {
4438                 struct bio *b;
4439                 int d = r10_bio->devs[s/2].devnum;
4440                 struct md_rdev *rdev;
4441                 if (s&1) {
4442                         rdev = conf->mirrors[d].replacement;
4443                         b = r10_bio->devs[s/2].repl_bio;
4444                 } else {
4445                         rdev = conf->mirrors[d].rdev;
4446                         b = r10_bio->devs[s/2].bio;
4447                 }
4448                 if (!rdev || test_bit(Faulty, &rdev->flags))
4449                         continue;
4450                 atomic_inc(&rdev->nr_pending);
4451                 md_sync_acct(b->bi_bdev, r10_bio->sectors);
4452                 atomic_inc(&r10_bio->remaining);
4453                 b->bi_next = NULL;
4454                 generic_make_request(b);
4455         }
4456         end_reshape_request(r10_bio);
4457 }
4458
4459 static void end_reshape(struct r10conf *conf)
4460 {
4461         if (test_bit(MD_RECOVERY_INTR, &conf->mddev->recovery))
4462                 return;
4463
4464         spin_lock_irq(&conf->device_lock);
4465         conf->prev = conf->geo;
4466         md_finish_reshape(conf->mddev);
4467         smp_wmb();
4468         conf->reshape_progress = MaxSector;
4469         conf->reshape_safe = MaxSector;
4470         spin_unlock_irq(&conf->device_lock);
4471
4472         /* read-ahead size must cover two whole stripes, which is
4473          * 2 * (datadisks) * chunksize where 'n' is the number of raid devices
4474          */
4475         if (conf->mddev->queue) {
4476                 int stripe = conf->geo.raid_disks *
4477                         ((conf->mddev->chunk_sectors << 9) / PAGE_SIZE);
4478                 stripe /= conf->geo.near_copies;
4479                 if (conf->mddev->queue->backing_dev_info.ra_pages < 2 * stripe)
4480                         conf->mddev->queue->backing_dev_info.ra_pages = 2 * stripe;
4481         }
4482         conf->fullsync = 0;
4483 }
4484
4485 static int handle_reshape_read_error(struct mddev *mddev,
4486                                      struct r10bio *r10_bio)
4487 {
4488         /* Use sync reads to get the blocks from somewhere else */
4489         int sectors = r10_bio->sectors;
4490         struct r10conf *conf = mddev->private;
4491         struct {
4492                 struct r10bio r10_bio;
4493                 struct r10dev devs[conf->copies];
4494         } on_stack;
4495         struct r10bio *r10b = &on_stack.r10_bio;
4496         int slot = 0;
4497         int idx = 0;
4498         struct bio_vec *bvec = r10_bio->master_bio->bi_io_vec;
4499
4500         r10b->sector = r10_bio->sector;
4501         __raid10_find_phys(&conf->prev, r10b);
4502
4503         while (sectors) {
4504                 int s = sectors;
4505                 int success = 0;
4506                 int first_slot = slot;
4507
4508                 if (s > (PAGE_SIZE >> 9))
4509                         s = PAGE_SIZE >> 9;
4510
4511                 while (!success) {
4512                         int d = r10b->devs[slot].devnum;
4513                         struct md_rdev *rdev = conf->mirrors[d].rdev;
4514                         sector_t addr;
4515                         if (rdev == NULL ||
4516                             test_bit(Faulty, &rdev->flags) ||
4517                             !test_bit(In_sync, &rdev->flags))
4518                                 goto failed;
4519
4520                         addr = r10b->devs[slot].addr + idx * PAGE_SIZE;
4521                         success = sync_page_io(rdev,
4522                                                addr,
4523                                                s << 9,
4524                                                bvec[idx].bv_page,
4525                                                READ, false);
4526                         if (success)
4527                                 break;
4528                 failed:
4529                         slot++;
4530                         if (slot >= conf->copies)
4531                                 slot = 0;
4532                         if (slot == first_slot)
4533                                 break;
4534                 }
4535                 if (!success) {
4536                         /* couldn't read this block, must give up */
4537                         set_bit(MD_RECOVERY_INTR,
4538                                 &mddev->recovery);
4539                         return -EIO;
4540                 }
4541                 sectors -= s;
4542                 idx++;
4543         }
4544         return 0;
4545 }
4546
4547 static void end_reshape_write(struct bio *bio)
4548 {
4549         struct r10bio *r10_bio = bio->bi_private;
4550         struct mddev *mddev = r10_bio->mddev;
4551         struct r10conf *conf = mddev->private;
4552         int d;
4553         int slot;
4554         int repl;
4555         struct md_rdev *rdev = NULL;
4556
4557         d = find_bio_disk(conf, r10_bio, bio, &slot, &repl);
4558         if (repl)
4559                 rdev = conf->mirrors[d].replacement;
4560         if (!rdev) {
4561                 smp_mb();
4562                 rdev = conf->mirrors[d].rdev;
4563         }
4564
4565         if (bio->bi_error) {
4566                 /* FIXME should record badblock */
4567                 md_error(mddev, rdev);
4568         }
4569
4570         rdev_dec_pending(rdev, mddev);
4571         end_reshape_request(r10_bio);
4572 }
4573
4574 static void end_reshape_request(struct r10bio *r10_bio)
4575 {
4576         if (!atomic_dec_and_test(&r10_bio->remaining))
4577                 return;
4578         md_done_sync(r10_bio->mddev, r10_bio->sectors, 1);
4579         bio_put(r10_bio->master_bio);
4580         put_buf(r10_bio);
4581 }
4582
4583 static void raid10_finish_reshape(struct mddev *mddev)
4584 {
4585         struct r10conf *conf = mddev->private;
4586
4587         if (test_bit(MD_RECOVERY_INTR, &mddev->recovery))
4588                 return;
4589
4590         if (mddev->delta_disks > 0) {
4591                 sector_t size = raid10_size(mddev, 0, 0);
4592                 md_set_array_sectors(mddev, size);
4593                 if (mddev->recovery_cp > mddev->resync_max_sectors) {
4594                         mddev->recovery_cp = mddev->resync_max_sectors;
4595                         set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
4596                 }
4597                 mddev->resync_max_sectors = size;
4598                 if (mddev->queue) {
4599                         set_capacity(mddev->gendisk, mddev->array_sectors);
4600                         revalidate_disk(mddev->gendisk);
4601                 }
4602         } else {
4603                 int d;
4604                 for (d = conf->geo.raid_disks ;
4605                      d < conf->geo.raid_disks - mddev->delta_disks;
4606                      d++) {
4607                         struct md_rdev *rdev = conf->mirrors[d].rdev;
4608                         if (rdev)
4609                                 clear_bit(In_sync, &rdev->flags);
4610                         rdev = conf->mirrors[d].replacement;
4611                         if (rdev)
4612                                 clear_bit(In_sync, &rdev->flags);
4613                 }
4614         }
4615         mddev->layout = mddev->new_layout;
4616         mddev->chunk_sectors = 1 << conf->geo.chunk_shift;
4617         mddev->reshape_position = MaxSector;
4618         mddev->delta_disks = 0;
4619         mddev->reshape_backwards = 0;
4620 }
4621
4622 static struct md_personality raid10_personality =
4623 {
4624         .name           = "raid10",
4625         .level          = 10,
4626         .owner          = THIS_MODULE,
4627         .make_request   = raid10_make_request,
4628         .run            = raid10_run,
4629         .free           = raid10_free,
4630         .status         = raid10_status,
4631         .error_handler  = raid10_error,
4632         .hot_add_disk   = raid10_add_disk,
4633         .hot_remove_disk= raid10_remove_disk,
4634         .spare_active   = raid10_spare_active,
4635         .sync_request   = raid10_sync_request,
4636         .quiesce        = raid10_quiesce,
4637         .size           = raid10_size,
4638         .resize         = raid10_resize,
4639         .takeover       = raid10_takeover,
4640         .check_reshape  = raid10_check_reshape,
4641         .start_reshape  = raid10_start_reshape,
4642         .finish_reshape = raid10_finish_reshape,
4643         .congested      = raid10_congested,
4644 };
4645
4646 static int __init raid_init(void)
4647 {
4648         return register_md_personality(&raid10_personality);
4649 }
4650
4651 static void raid_exit(void)
4652 {
4653         unregister_md_personality(&raid10_personality);
4654 }
4655
4656 module_init(raid_init);
4657 module_exit(raid_exit);
4658 MODULE_LICENSE("GPL");
4659 MODULE_DESCRIPTION("RAID10 (striped mirror) personality for MD");
4660 MODULE_ALIAS("md-personality-9"); /* RAID10 */
4661 MODULE_ALIAS("md-raid10");
4662 MODULE_ALIAS("md-level-10");
4663
4664 module_param(max_queued_requests, int, S_IRUGO|S_IWUSR);